Substrate treatment method and substrate treatment apparatus

ABSTRACT

A substrate treatment method for treating a substrate by supplying a treatment liquid to the substrate while rotating the substrate. The method comprises the steps of: performing a first substrate rotation process for rotating the substrate while clamping the substrate by a first clamping member set; performing a second substrate rotation process after the first substrate rotation step for rotating the substrate while clamping the substrate by the first clamping member set and a second clamping member set provided separately from the first clamping member set; and performing a third substrate rotation process after the second substrate rotation step by unclamping the substrate from the first clamping member set for rotating the substrate while clamping the substrate by the second clamping member set.

CROSS REFERENCE TO A RELATED APPLICATION

The present application is a Divisional Application of Ser. No.10/623,927 filed Jul. 21, 2003 now U.S. Pat. No. 7,018,555, whichapplication claims the benefit and priority of Japanese ApplicationSerial No. 2002-218723, filed Jul. 26, 2002, Japanese Application SerialNo. 2002-218724, filed Jul. 26, 2002, Japanese Application Serial No.2003-083695, filed Mar. 25, 2003 and Japanese Application Serial No.2003-083696 filed Mar. 25, 2003, incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate treatment method and asubstrate treatment apparatus for treating a substrate (particularly,treating a substrate with a treatment fluid such as a treatment liquid)while rotating the substrate. Examples of the substrate to be treatedinclude various types of substrates such as semiconductor wafers, glasssubstrates for liquid crystal display devices, glass substrates forplasma display panels, substrates for optical disks, substrates formagnetic disks, substrates for magneto-optical disks and substrates forphoto-masks.

2. Description of Related Arts

In the production of a semiconductor device, an etching process is oftenperformed, after a thin metal film such as a thin copper film is formedon the entire front surface and peripheral surface (and the entire rearsurface in some case) of a semiconductor substrate (hereinafter referredto simply as “wafer”), for etching away unnecessary portions of the thinmetal film. For example, a thin copper film for wiring is merelyrequired to be provided in a device formation region on the frontsurface of the wafer, so that portions of the copper thin film presenton a peripheral edge portion of the front surface of the wafer (having awidth of about 5 mm as measured from the peripheral edge of the wafer)and the peripheral surface and rear surface of the wafer areunnecessary. In addition, metallic or ionic copper deposited on theperipheral edge portion, the rear surface and the peripheral surface islikely to contaminate a hand of a substrate transport robot provided ina substrate treatment apparatus, and the contamination may betransferred to another substrate held by the hand.

Similarly, a non-metallic film (such as an oxide film or a nitride film)formed on the peripheral surface of the substrate is thinly etched forremoval of metal contaminants (including metal ions) from the surface.

A typical substrate periphery treatment apparatus for selectivelyetching away portions of a thin film from the peripheral edge portionand peripheral surface of a wafer includes, for example, a spin chuckfor rotating the wafer while horizontally holding the wafer, a shieldplate provided above the spin chuck for limiting a space above thewafer, and an etching liquid supply nozzle for supplying an etchingliquid to a lower surface of the wafer. The etching liquid supplied tothe lower surface of the wafer flows over the lower surface of the waferradially outwardly from a rotation center by a centrifugal force, andfurther flows over the peripheral surface of the wafer onto an uppersurface of the wafer, whereby unnecessary substances are etched awayfrom the peripheral edge portion of the upper surface of the wafer. Atthis time, the shield plate is located adjacent the upper surface of thewafer, and an inert gas such as nitrogen gas is supplied to the spacebetween the shield plate and the wafer.

The amount of the etching liquid flowing onto the upper surface can becontrolled by properly adjusting the flow rate of the inert gas and therotation speed of the spin chuck, so that a peripheral edge portion ofthe upper surface of the wafer having a predetermined width (e.g., 1 to7 mm) can selectively be subjected to the etching process (so-calledbevel etching process).

The spin chuck includes a vertical rotary shaft, a spin base fixed to anupper end of the rotary shaft, and three chuck pins provided upright ona peripheral edge portion of the spin base. A torque is applied to therotary shaft with the peripheral surface of the wafer clamped by thechuck pins, whereby the wafer is rotated together with the spin base.

During the rotation of the wafer held by the spin chuck, the unnecessarysubstances are etched away from the peripheral edge portion of the uppersurface of the wafer by supplying the etching liquid to the lowersurface of the wafer. After the upper and lower surfaces of the waferare rinsed with deionized water, the spin chuck is rotated at a highspeed to spin off water droplets from the upper and lower surfaces ofthe wafer for drying the wafer.

With this arrangement, however, the wafer is constantly clamped by thechuck pins, so that portions of the peripheral surface of the wafer keptin abutment against the chuck pins are liable to suffer from a treatmentfailure such as insufficient etching, insufficient rinsing orinsufficient drying.

One approach to this problem is to once stop the rotation of the spinchuck during the treatment, then change wafer clamping positions andresume the rotation of the spin chuck. However, this approach isdisadvantageous because the treatment time per wafer is prolonged andthe productivity is drastically reduced.

Another conventional approach is disclosed in Japanese Unexamined PatentPublication No. 2001-118824, in which the wafer clamping positions arechanged without stopping the rotation of the spin chuck by completely orslightly releasing the wafer from the chuck pins to relatively rotate(or slide) the wafer with respect to the spin chuck and then clampingthe wafer again by the chuck pins during the rotation of the spin chuck.

In this conventional approach, however, the wafer is kept in slidingcontact with the chuck pins of the spin chuck, because the waferclamping positions are changed by sliding the wafer on the spin chuck.This results in generation of particles.

In the conventional approach described above, an air cylinder and a linkmechanism are incorporated in the spin base for driving the chuck pins,and compressed air is supplied for driving the spin base. Thiscomplicates the construction of the apparatus, making the waferclamping/unclamping motions of the chuck pins unstable.

With the aforesaid arrangement, the chuck pins are kept in slidingcontact with the peripheral surface of the wafer during the relativerotation of the wafer with respect to the spin chuck, so that the chuckpins are abraded.

Further, the degree of the relative rotation of the wafer with respectto the spin chuck cannot accurately be controlled, so that therotational position of the wafer cannot be controlled.

When the wafer is unclamped from the chuck pins during the treatment, aminute spacing between the wafer and the shield plate cannot be keptconstant. This makes it impossible to accurately control the amount ofthe etching liquid flowing onto the front surface from the rear surfaceof the wafer.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide a substratetreatment apparatus and a substrate treatment method, wherein substrateclamping positions can be changed during rotation of a substrate.

It is another object of the present invention to provide a substratetreatment method and a substrate treatment apparatus, wherein substrateclamping positions can be changed during rotation of a substrate andgeneration of particles can be suppressed so that the substrate canproperly be treated.

It is further another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereinsubstrate clamping positions can be changed during rotation of asubstrate so that the substrate can properly be treated withoutreduction in productivity.

It is still another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereina substrate can be clamped and unclamped by clamping members duringrotation of the substrate with a simplified construction.

It is further another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereinan operation mode can be switched between a mode in which clampingmembers are kept in a substrate clamping/unclamping state and a mode inwhich the clamping members are kept in a substrate clamping state or ina substrate unclamping state.

It is still another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereinabrasion of a component can be suppressed and a high-quality substratetreatment can be achieved by rotating a substrate while stably holdingthe substrate.

It is further another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereinthe rotational position of a substrate can easily be controlled.

It is still another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereina peripheral edge portion of a substrate can properly be treated.

It is further another object of the present invention to provide asubstrate treatment apparatus and a substrate treatment method, whereina substrate can constantly stably be held during a substrate treatment.

According to one aspect of the present invention, there is provided asubstrate treatment method for treating a substrate by supplying atreatment liquid to the substrate while rotating the substrate, themethod comprising the steps of: performing a first substrate rotationprocess for rotating the substrate while clamping the substrate by afirst clamping member set including at least two clamping members;performing a second substrate rotation process after the first substraterotation step for rotating the substrate while clamping the substrate bythe first clamping member set and a second clamping member set providedseparately from the first clamping member set and including at least twoclamping members; and performing a third substrate rotation processafter the second substrate rotation step by unclamping the substratefrom the first clamping member set for rotating the substrate whileclamping the substrate by the second clamping member set.

In this method, a substrate clamping state can be once switched from afirst clamping state where the substrate is clamped by the firstclamping member set and unclamped by the second clamping member set toan intermediate state where the substrate is clamped by the first andsecond clamping member sets, and then to a second clamping state wherethe substrate is clamped by the second clamping member set and unclampedby the first clamping member set while the substrate is continuouslyrotated. Thus, substrate clamping positions can be changed even duringthe rotation of the substrate.

With this arrangement, the entire surface of the substrate can properlybe treated with the treatment liquid. In addition, there is no need tostop the rotation of the substrate for changing the substrate clampingpositions, thereby preventing the reduction in productivity.

Further, the substrate is unlikely to be brought into sliding contactwith the clamping members, so that the generation of particles can besuppressed. Thus, the substrate treatment can properly be performed.

Particularly, when the substrate clamping state is switched from thefirst clamping state to the second clamping state, the substrate is onceclamped by both the first clamping member set and the second clampingmember set in the intermediate state. Therefore, the substrate isconstantly clamped by either or both of the first and second clampingmember sets during the rotation of the substrate. Hence, the substrateis unlikely to be slid even during the switching from the first clampingstate to the second clamping state, whereby the generation of particlescan assuredly be suppressed.

The first clamping member set preferably includes at least threesubstrate clamp pins (e.g., abutment portions 96, A, B of clampingmembers F1 to F3 in embodiments to be described later). The secondclamping member set preferably includes at least three substrate clamppins (e.g., abutment portions 96, C, D of clamping members S1 to S3 inthe embodiments to be described later).

In this case, the substrate clamp pins each have a smaller contact areawith respect to the substrate for proper treatment of a peripheral edgeportion of the substrate. Since the at least three clamp pins areemployed, the substrate can assuredly be held.

The method preferably further comprises the step of supplying thetreatment liquid to a surface of the substrate being rotated at least inthe first substrate rotation step and the third substrate rotation step.The substrate is clamped at different substrate clamping positions inthe first substrate rotation step and in the third substrate rotationstep. Therefore, the entire surface of the substrate can be treated withthe treatment liquid.

The treatment liquid supply step preferably comprises the step ofsupplying an etching liquid for etching away an unnecessary substancefrom the peripheral edge portion of the substrate. This makes itpossible to perform a process for removing the unnecessary substancefrom the peripheral edge portion of the substrate. Since the substrateis clamped at different substrate clamping positions in the firstsubstrate rotation step and in the third substrate rotation step asdescribed above, the entire peripheral edge portion of the substrate canproperly be treated.

Examples of the process for removing the unnecessary substance from theperipheral edge portion of the substrate include a process for etchingaway an unnecessary thin film from the peripheral edge portion of thesubstrate (so-called bevel etching process) and a process for removingunwanted particles or metal contaminants from the peripheral edgeportion of the substrate (so-call bevel cleaning process).

The method may further comprise the step of supplying the treatmentliquid to the substrate prior to the first substrate rotation step. Inthis case, the treatment liquid is not supplied to the substrate duringany of the first substrate rotation step, the second substrate rotationstep and the third substrate rotation step, but a drying process may beperformed by spinning off the treatment liquid by the rotation of thesubstrate. The substrate is clamped at different substrate clampingpositions in the first substrate rotation step and in the thirdsubstrate rotation step. Therefore, the entire surface of the substratecan properly be dried without the treatment liquid remaining at thesubstrate clamping positions.

The clamping members of at least one of the first clamping member setand the second clamping member set may each have at least two abutmentportions which are selectively brought into abutment against thesubstrate. In this case, the method preferably further comprises thestep of switchably bringing the at least two abutment portions intoabutment against the substrate. Since the clamping members each have theat least two abutment portions, the substrate is clamped switchably atleast at two different substrate abutting positions by each of theclamping members. That is, the substrate abutting positions can bechanged by driving the clamping members to switchably bring the abutmentportions into abutment against the substrate in the abutment portionswitching step.

Therefore, the first and second clamping member sets can change thesubstrate abutting positions in at least three ways for clamping thesubstrate by employing two driving mechanisms respectively provided fordriving the first and second clamping member sets. As a result, thesubstrate abutting positions are each covered with the correspondingabutment portions only for a limited period, so that the total substratetreatment period can be reduced.

More specifically, it is herein assumed that the treatment liquid shouldbe supplied to the entire peripheral edge portion of the substrate forat least 60 seconds. Where the clamping member sets can change thesubstrate abutting positions only in two ways, it is impossible toreduce the treatment period to shorter than 120 seconds because thetreatment liquid should be supplied to each of the substrate abuttingpositions for 60 seconds. On the contrary, where the clamping membersets can change the substrate abutting positions in four ways, forexample, it is merely necessary to clamp the substrate in each of thefour ways for 20 seconds so as to supply the treatment liquid to each ofthe substrate abutting positions for 60 seconds in total. That is, thetreatment period can be reduced to about 80 seconds.

The first clamping member set may include three clamping members eachhaving a first abutment portion and a second abutment portion which areselectively brought into abutment against the substrate, and the secondclamping member set may include three clamping members each having athird abutment portion which is brought into abutment against thesubstrate. In this case, the first substrate rotation step preferablycomprises the step of bringing the first abutment portions of the threeclamping members of the first clamping member set into abutment againstthe substrate for clamping the substrate. The second substrate rotationstep preferably comprises the step of bringing the third abutmentportions of the three clamping members of the second clamping member setinto abutment against the substrate with the first abutment portions ofthe three clamping members of the first clamping member set kept inabutment against the substrate. The third substrate rotation steppreferably comprises the step of retracting the first abutment portionsof the three clamping members of the first clamping member set from thesubstrate. The method preferably further comprises the steps of:performing a fourth substrate rotation process after the third substraterotation step by bringing the second abutment portions of the threeclamping members of the first clamping member set into abutment againstthe substrate with the third abutment portions of the three clampingmembers of the second clamping member set kept in abutment against thesubstrate for rotating the substrate while clamping the substrate by thefirst and second clamping member sets; and performing a fifth substraterotation process after the fourth substrate rotation step by retractingthe third abutment portions of the three clamping members of the secondclamping member set from the substrate to unclamp the substrate from thesecond clamping member set for rotating the substrate while clamping thesubstrate by the first substrate clamping member set.

In the first substrate rotation step, the substrate is rotated whilebeing stably clamped by the three first abutment portions. In the secondsubstrate rotation step, the substrate is rotated while being stablyclamped by a total of six abutment portions, i.e., the three firstabutment portions and the three third abutment portions. In the thirdsubstrate rotation step, the substrate is rotated while being stablyclamped by the three third abutment portions. In the fourth substraterotation step, the substrate is rotated while being stably clamped by atotal of six abutment portions, i.e., the three second abutment portionsand the three third abutment portions. In the fifth substrate rotationstep, the substrate is rotated while being stably clamped by the threesecond abutment portions. Thus, the substrate clamping state is onceswitched from a state where the substrate is clamped by the three firstabutment portions to an intermediate state where the substrate isclamped by the six abutment portions including the three first abutmentportions and the three third abutment portions, and then to a statewhere the substrate is clamped by the three third abutment portions.Then, the substrate clamping state is further switched to anintermediate state where the substrate is clamped by the three thirdabutment portions and the three second abutment portions, and then to astate where the substrate is clamped by the three second abutmentportions.

The three clamping members of the second clamping member set may eachhave the third abutment portion and a fourth abutment portion which areselectively brought into abutment against the substrate. In this case,the method preferably further comprises the steps of: performing a sixthsubstrate rotation process after the fifth substrate rotation step bybringing the fourth abutment portions of the three clamping members ofthe second clamping member set into abutment against the substrate withthe second abutment portions of the three clamping members of the firstclamping member set kept in abutment against the substrate for rotatingthe substrate while clamping the substrate by the first and secondclamping member sets; and performing a seventh substrate rotationprocess after the sixth substrate rotation step by retracting the secondabutment portions of the three clamping members of the first clampingmember set from the substrate to unclamp the substrate from the firstclamping member set for rotating the substrate while clamping thesubstrate only by the second clamping member set.

In the sixth substrate rotation step of this method, the substrate isrotated while being stably clamped by a total of six abutment portions,i.e., the three second abutment portions and the three fourth abutmentportions. In the seventh substrate rotation step, the substrate isrotated while being stably clamped by the three fourth abutmentportions. Thus, the substrate clamping state is once switched to anintermediate state where the substrate is clamped by the three secondabutment portions and the three fourth abutment portions, and then to astate where the substrate is clamped by the three fourth abutmentportions.

The method may further comprise the steps of: performing an eighthsubstrate rotation process after the seventh substrate rotation step bybringing the first abutment portions of the three clamping members ofthe first clamping member set into abutment against the substrate withthe fourth abutment portions of the three clamping members of the secondclamping member set kept in abutment against the substrate for rotatingthe substrate while clamping the substrate by the first and secondclamping member sets; and retracting the fourth abutment portions of thethree clamping members of the second clamping member set from thesubstrate after the eighth substrate rotation step and repeating aprocess sequence starting from the first substrate rotation step.

Thus, the substrate clamping state can be once switched to anintermediate state where the substrate is clamped by the three fourthabutment portions and the three first abutment portions, and then backto the state where the substrate is rotated while being clamped by thethree first abutment portions.

The method preferably comprises the step of supplying the treatmentliquid to the surface of the substrate being rotated at least in thefirst substrate rotation step, the third substrate rotation step and thefifth substrate rotation step. In the first to fifth substrate rotationsteps, the substrate clamping positions are changed, so that the entiresurface of the substrate can be treated with the treatment liquid.

Further, the method preferably comprises the step of supplying thetreatment liquid to the surface of the substrate being rotated at leastin the first substrate rotation step, the third substrate rotation step,the fifth substrate rotation step and the seventh substrate rotationstep. In the first to seventh substrate rotation steps, the substrateclamping positions are changed, so that the entire surface of thesubstrate can be treated with the treatment liquid.

The treatment liquid supply step may comprise the step of supplying theetching liquid for etching away an unnecessary substance from theperipheral edge portion of the substrate. Thus, the entire peripheraledge portion of the substrate can properly be subjected to theunnecessary substance removal process.

The method may further comprise the step of supplying the treatmentliquid to the substrate prior to the first substrate rotation step. Inthis case, the treatment liquid is not supplied to the substrate duringany of the first to fifth substrate rotation steps, but the dryingprocess may be performed by spinning off the treatment liquid by therotation of the substrate.

Alternatively, the method may further comprise the step of supplying thetreatment liquid to the substrate prior to the first substrate rotationstep, wherein the treatment liquid is not supplied to the substrateduring any of the first to seventh substrate rotation steps, but thedrying process is performed by spinning off the treatment liquid by therotation of the substrate.

With these arrangements, the drying process can be performed while thesubstrate clamping positions are changed. Therefore, the entire surfaceof the substrate can properly be dried without the treatment liquidremaining at the substrate clamping positions.

According to another aspect of the present invention, there is provideda substrate treatment apparatus for treating a substrate by supplying atreatment liquid to the substrate while rotating the substrate, theapparatus comprising: a substrate holding mechanism comprising a firstclamping member set including at least two clamping members and a secondclamping member set provided separately from the first clamping memberset and including at least two clamping members; a rotative drivemechanism for rotating the substrate holding mechanism; a first clampingmember drive mechanism for driving the first clamping member set; asecond clamping member drive mechanism for driving the second clampingmember set; and a controller for controlling the rotative drivemechanism, the first clamping member drive mechanism and the secondclamping member drive mechanism to perform a first substrate rotationprocess for rotating the substrate holding mechanism while clamping thesubstrate by the first clamping member set, to perform a secondsubstrate rotation process after the first substrate rotation processfor rotating the substrate holding mechanism while clamping thesubstrate by the first clamping member set and the second clampingmember set, and to perform a third substrate rotation process after thesecond substrate rotation process by unclamping the substrate from thefirst clamping member set for rotating the substrate holding mechanismwhile clamping the substrate by the second clamping member set.

The clamping members of at least one of the first clamping member setand the second clamping member set may each have at least two abutmentportions which are selectively brought into abutment against thesubstrate. In this case, the controller preferably performs an abutmentportion switching process for switchably bringing the at least twoabutment portions into abutment against the substrate.

According to further another aspect of the present invention, there isprovided a substrate treatment apparatus for treating a substrate bysupplying a treatment liquid while rotating the substrate, the apparatuscomprising: a substrate holding mechanism comprising a first clampingmember set including at least two clamping members and a second clampingmember set provided separately from the first clamping member set andincluding at least two clamping members; a rotative drive mechanism forrotating the substrate holding mechanism; a first clamping member drivemechanism for driving the first clamping member set; a second clampingmember drive mechanism for driving the second clamping member set; and acontroller for independently controlling the first clamping member drivemechanism and the second clamping member drive mechanism.

With this arrangement, the first and second clamping member sets canindependently be operated, so that first, second and third substraterotation processes as described above can properly be performed.

The controller is preferably capable of controlling the first clampingmember drive mechanism and the second clamping member drive mechanism soas to clamp the substrate by both the first clamping member set and thesecond clamping member set. With this arrangement, the second substraterotation process described above can properly be performed.

The substrate holding mechanism may comprise a rotary member rotatableabout a rotary shaft thereof. The first clamping member drive mechanismmay comprise a first non-rotative movable member which is movableparallel to the rotary shaft, a first driving mechanism for moving thefirst non-rotative movable member parallel to the rotary shaft, a firstrotative movable member which is movable parallel to the rotary shaft inassociation with movement of the first non-rotative movable member by adriving force received from the first non-rotative movable member and isrotatable together with the rotary member, and a first movementconverting mechanism for converting movement of the first rotativemovable member into movement of the first substrate clamping member set.Further, the second clamping member drive mechanism may comprise asecond non-rotative movable member which is movable parallel to therotary shaft, a second driving mechanism for moving the secondnon-rotative movable member parallel to the rotary shaft, a secondrotative movable member which is movable parallel to the rotary shaft inassociation with movement of the second non-rotative movable member by adriving force received from the second non-rotative movable member andis rotatable together with the rotary member, and a second movementconverting mechanism for converting movement of the second rotativemovable member into movement of the second substrate clamping memberset.

With this arrangement, when the first and second non-rotative movablemembers are respectively moved by the first and second drivingmechanisms, the first and second rotative movable members arerespectively moved by the driving forces received from the first andsecond non-rotative movable members. The movements of the first andsecond rotative movable members are converted into the movements of theclamping members for clamping and unclamping the substrate.

That is, the first and second rotative movable members are rotatedtogether with the rotary member (in a rotative state), while the firstand second non-rotative movable members are kept still (in anon-rotative state) Therefore, the movements of the first and secondrotative movable members can respectively be converted into themovements of the clamping members by the first and second movementconverting mechanisms without relative rotation of the first and secondrotative movable members with respect to the rotary member even duringthe rotation of the rotary member.

In this manner, the substrate can be completely or slightly releasedfrom the clamping members and then clamped again by the clamping memberseven during the rotation of the rotary member. Thus, the clampingmembers can change substrate clamping positions even during the rotationof the substrate.

At least one of the first non-rotative movable member and the firstrotative movable member may be configured annularly about the rotaryshaft. Further, at least one of the second non-rotative movable memberand the second rotative movable member may be configured annularly aboutthe rotary shaft.

The substrate treatment apparatus may further comprise a first annularbearing as a first driving force transmission mechanism for transmittingthe driving force from the first non-rotative movable member to thefirst rotative movable member, the first bearing coupling the firstnon-rotative movable member and the first rotative movable member so asto permit relative rotation of the first rotative movable member withrespect to the first non-rotative movable member about the rotary shaft.

The first bearing may have a stationary ring provided around the rotaryshaft and coupled to the first non-rotative movable member, and a rotaryring coupled to the first rotative movable member and rotatable relativeto the stationary ring about the rotary shaft.

With this arrangement, the first rotative movable member can be rotatedtogether with the rotary member (in a rotative state), while the firstnon-rotative movable member is kept still (in a non-rotative state).

The first driving force transmission mechanism may comprise a pluralityof first rolling members provided on at least one of the firstnon-rotative movable member and the first rotative movable member so asto be rolled on a surface of the other movable member.

With this arrangement, the first rotative movable member can be rotatedtogether with the rotary member (in a rotative state), while the firstnon-rotative movable member is kept still (in a non-rotative state).

The first driving force transmission mechanism may comprise a firststationary magnet and a first rotary magnet respectively provided on thefirst non-rotative movable member and the first rotative movable memberwith opposed poles thereof having the same polarity.

This arrangement constitutes a so-called magnetic bearing. Therefore,the first rotative movable member can be rotated together with therotary member (in a rotative state), while the first non-rotativemovable member is kept still (in a non-rotative state). In addition, thefirst rotative movable member can be supported in a non-contact mannerby magnetic levitation, while the relative rotation of the firstrotative movable member with respect to the first non-rotative movablemember is permitted.

Further, the first driving force transmission mechanism may comprise afirst gas supply mechanism for supplying a gas between the firstnon-rotative movable member and the first rotative movable member so asto keep the first non-rotative movable member and the first rotativemovable member in spaced relation.

This arrangement constitutes a so-called pneumatic bearing. Therefore,the first rotative movable member can be rotated together with therotary member (in a rotative state), while the first non-rotativemovable member is kept still (in a non-rotative state). In addition, thefirst rotative movable member can be supported in a non-contact mannerby pneumatic levitation, while the relative rotation of the firstrotative movable member with respect to the first non-rotative movablemember is permitted.

The substrate treatment apparatus may further comprise a second annularbearing as a second driving force transmission mechanism fortransmitting the driving force from the second non-rotative movablemember to the second rotative movable member, the second bearingcoupling the second non-rotative movable member and the second rotativemovable member so as to permit relative rotation of the second rotativemovable member with respect to the second non-rotative movable memberabout the rotary shaft.

The second bearing may have a stationary ring provided around the rotaryshaft and coupled to the second non-rotative movable member, and arotary ring coupled to the second rotative movable member and rotatablerelative to the stationary ring about the rotary shaft.

The second driving force transmission mechanism may comprise a pluralityof second rolling members provided on at least one of the secondnon-rotative movable member and the second rotative movable member so asto be rolled on a surface of the other movable member.

The second driving force transmission mechanism may comprise a secondstationary magnet and a second rotary magnet respectively provided onthe second non-rotative movable member and the second rotative movablemember with opposed poles thereof having the same polarity.

The second driving force transmission mechanism may comprise a secondgas supply mechanism for supplying a gas between the second non-rotativemovable member and the second rotative movable member so as to keep thesecond non-rotative movable member and the second rotative movablemember in spaced relation.

The first driving mechanism and the second driving mechanism preferablycomprise a first driving force source and a second driving force source,respectively, which are independently controllable.

With this arrangement, the substrate can be clamped switchably by thefirst clamping member set (first substrate clamping mechanism) and bythe second clamping member set (second substrate clamping mechanism),because the first substrate clamping mechanism and the second substrateclamping mechanism can independently be operated.

More specifically, the controller controls the first and second drivingmechanisms to switch a substrate clamping state between a first clampingstate where the substrate is clamped by the clamping members of thefirst substrate clamping mechanism and unclamped by the clamping membersof the second substrate clamping mechanism and a second clamping statewhere the substrate is clamped by the clamping members of the secondsubstrate clamping mechanism and unclamped by the clamping members ofthe first substrate clamping mechanism when the rotary member is rotatedby the rotative drive mechanism.

This arrangement obviates the need for relatively rotating (or sliding)the substrate with respect to the rotary member when the substrateclamping positions are changed. Therefore, the generation of particlescan be suppressed without sliding contact of the substrate with anycomponents of the rotary member.

The controller preferably further controls the first and second drivingmechanisms so as to switch the substrate clamping state to anintermediate state where the substrate is clamped by the clampingmembers of the first substrate clamping mechanism and the clampingmembers of the second substrate clamping mechanism when the substrateclamping state is switched between the first clamping state and thesecond clamping state.

With this arrangement, the substrate is once clamped by both the firstsubstrate clamping mechanism and the second substrate clamping mechanismin the intermediate state when the substrate clamping state is switchedfrom the first clamping state effected by the first substrate clampingmechanism to the second clamping state effected by the second substrateclamping mechanism. Thus, the substrate is constantly clamped by some orall of the clamping members during the rotation of the rotary member.Therefore, the generation of particles due to the sliding of thesubstrate can be suppressed, and the substrate is prevented fromspinning out when the substrate clamping state is switched from thefirst clamping state to the second clamping state.

The apparatus may further comprise a first relative rotation restrictingmechanism for restricting the relative rotation of the first rotativemovable member with respect to the rotary member. The apparatus mayfurther comprise a second relative rotation restricting mechanism forrestricting the relative rotation of the second rotative movable memberwith respect to the rotary member. The first relative rotationrestricting mechanism may comprise a first guide mechanism which isrotatable together with the rotary member and guides the first rotativemovable member parallel to the rotary shaft. The second relativerotation restricting mechanism may comprise a second guide mechanismwhich is rotatable together with the rotary member and guides the secondrotative movable member parallel to the rotary shaft.

According to still another aspect of the present invention, there isprovided a substrate treatment apparatus, which comprises: a rotarymember having a rotary shaft and a plurality of clamping members whichare capable of clamping and unclamping a substrate, the rotary memberbeing rotatable about the rotary shaft; a rotative drive mechanism forapplying a torque to the rotary shaft to rotatively drive the rotarymember; a non-rotative movable member which is movable parallel to therotary shaft; a driving mechanism for moving the non-rotative movablemember parallel to the rotary shaft; a rotative movable member which ismovable parallel to the rotary shaft in association with movement of thenon-rotative movable member by a driving force received from thenon-rotative movable member and is rotatable together with the rotarymember; a movement converting mechanism for converting movement of therotative movable member into movements of the clamping members of therotary member; and a controller for operating the driving mechanism sothat the substrate is completely or slightly released from the clampingmembers and then clamped again by the clamping members while the rotarymember is rotated by the rotative drive mechanism.

With this arrangement, when the non-rotative movable member is moved bythe driving mechanism, the rotative movable member is moved by thedriving force received from the non-rotative movable member. Themovement of the rotative movable member is converted into the movementsof the clamping members for clamping and unclamping the substrate.

That is, the rotative movable member can be rotated together with therotary member (in a rotative state), while the non-rotative movablemember is kept still (in a non-rotative state). Therefore, the movementof the rotative movable member can be converted in to the movements ofthe clamping members by the movement converting mechanism withoutrelative rotation of the rotative movable member with respect to therotary member even during the rotation of the rotary member.

In this manner, the substrate can be completely or slightly releasedfrom the clamping members and then clamped again by the clamping memberseven during the rotation of the rotary member. Thus, the clampingmembers can change substrate clamping positions during the rotation ofthe substrate.

The apparatus may further comprise a relative rotation restrictingmechanism for restricting the relative rotation of the rotative movablemember with respect to the rotary member. The relative rotationrestricting mechanism may comprise a guide mechanism which is rotatabletogether with the rotary member and guides the rotative movable memberparallel to the rotary shaft.

At least one of the non-rotative movable member and the rotative movablemember may be configured annularly about the rotary shaft.

The controller may control the rotative drive mechanism to accelerate ordecelerate the rotation of the rotary member when the substrate iscompletely or slightly released from the clamping members.

With this arrangement, the rotation of the rotary member is acceleratedor decelerated when the substrate is completely or slightly releasedfrom the clamping members. Therefore, the substrate is inertiallyrotated relative to the rotary member. Thus, the substrate clampingpositions can assuredly be changed.

The clamping members may each have a first abutment portion and a secondabutment portion which are selectively brought into abutment against thesubstrate. In this case, the controller preferably operates the drivingmechanism so that the first abutment portion and the second abutmentportion are switchably brought into abutment against the substrateduring the rotation of the rotary member.

With this arrangement, the first abutment portions and the secondabutment portions of the clamping members are switchably brought intoabutment against the substrate by operating the driving mechanism, sothat the substrate can be clamped by either the first abutment portionsor the second abutment portions. Therefore, the substrate clampingpositions can be changed by the switching between the first abutmentportions and the second abutment portions even during the rotation ofthe substrate.

The substrate treatment apparatus preferably further comprises anannular bearing as a driving force transmission mechanism fortransmitting the driving force from the non-rotative movable member tothe rotative movable member, the bearing coupling the non-rotativemovable member and the rotative movable member so as to permit relativerotation of the rotative movable member with respect to the non-rotativemovable member about the rotary shaft.

The bearing may comprise a stationary ring provided around the rotaryshaft and coupled to the non-rotative movable member, and a rotary ringcoupled to the rotative movable member and rotatable relative to thestationary ring about the rotary shaft.

With this arrangement, the rotative movable member can be rotatedtogether with the rotary member (in a rotative state), while thenon-rotative movable member is kept still (in a non-rotative state).

The driving force transmission mechanism may comprise a plurality ofrolling members provided on at least one of the non-rotative movablemember and the rotative movable member so as to be rolled on a surfaceof the other movable member.

With this arrangement, the rotative movable member can be rotatedtogether with the rotary member (in a rotative state), while thenon-rotative movable member is kept still (in a non-rotative state).

The driving force transmission mechanism may comprise a stationarymagnet and a rotary magnet respectively provided on the non-rotativemovable member and the rotative movable member with opposed polesthereof having the same polarity.

This arrangement constitutes a so-called magnetic bearing. Therefore,the rotative movable member can be rotated together with the rotarymember (in a rotative state), while the non-rotative movable member iskept still (in a non-rotative state). In addition, the rotative movablemember can be supported in a non-contact manner by magnetic levitation,while the relative rotation of the rotative movable member with respectto the non-rotative movable member is permitted.

Further, the driving force transmission mechanism may comprise a gassupply mechanism for supplying a gas between the non-rotative movablemember and the rotative movable member so as to keep the non-rotativemovable member and the rotative movable member in spaced relation.

This arrangement constitutes a so-called pneumatic bearing. Therefore,the rotative movable member can be rotated together with the rotarymember (in a rotative state), while the non-rotative movable member iskept still (in a non-rotative state). In addition, the rotative movablemember can be supported in a non-contact manner by pneumatic levitation,while the relative rotation of the rotative movable member with respectto the non-rotative movable member is permitted.

According to further another aspect of the present invention, there isprovided a substrate treatment method, which comprises the steps of:providing a rotary member rotatable about a rotary shaft and having aplurality of clamping members which are capable of clamping andunclamping a substrate; providing a non-rotative movable member which ismovable parallel to the rotary shaft; providing a rotative movablemember which is movable parallel to the rotary shaft in association withmovement of the non-rotative movable member by a driving force receivedfrom the non-rotative movable member and is rotatable together with therotary member; providing a movement converting mechanism for convertingmovement of the rotative movable member into movements of the clampingmembers of the rotary member; rotating the rotary member by a rotativedrive mechanism; moving the non-rotative movable member parallel to therotary shaft to completely or slightly release the substrate from theclamping members in the rotary member rotation step; and moving thenon-rotative movable member parallel to the rotary shaft to clamp thesubstrate again by the clamping members after the complete/slightrelease step.

The method preferably further comprises the step of controlling therotative drive mechanism to accelerate or decelerate the rotation of therotary member in the complete/slight release step.

According to still another aspect of the present invention, there isprovided a substrate treatment method, which comprises the steps of:providing a rotary member rotatable about a rotary shaft and comprisinga first substrate clamping mechanism and a second substrate clampingmechanism each having a plurality of clamping members which are capableof clamping and unclamping a substrate; providing a first non-rotativemovable member which is movable parallel to the rotary shaft; providinga second non-rotative movable member which is movable parallel to therotary shaft; providing a first rotative movable member which is movableparallel to the rotary shaft in association with movement of the firstnon-rotative movable member by a driving force received from the firstnon-rotative movable member and is rotatable together with the rotarymember; providing a second rotative movable member which is movableparallel to the rotary shaft in association with movement of the secondnon-rotative movable member by a driving force received from the secondnon-rotative movable member and is rotatable together with the rotarymember; providing a first movement converting mechanism for convertingmovement of the first rotative movable member into movement of the firstsubstrate clamping mechanism of the rotary member; providing a secondmovement converting mechanism for converting movement of the secondrotative movable member into movement of the second substrate clampingmechanism of the rotary member; performing a first clamping process bycontrolling positions of the first and second non-rotative movablemembers along the rotary shaft for keeping a substrate clamping state ina first clamping state where the substrate is clamped by the clampingmembers of the first substrate clamping mechanism and unclamped by theclamping members of the second substrate clamping mechanism; performinga second clamping process by controlling the positions of the first andsecond non-rotative movable members along the rotary shaft for keepingthe substrate clamping state in a second clamping state where thesubstrate is clamped by the clamping members of the second substrateclamping mechanism and unclamped by the clamping members of the firstsubstrate clamping mechanism; and switching the substrate clamping statebetween the first clamping state and the second clamping state when therotary member is rotated by a rotative drive mechanism.

The switching step may comprise the step of controlling first and seconddriving mechanisms, which drive the first and second non-rotativemovable members, respectively, so as to switch the substrate clampingstate to an intermediate state where the substrate is clamped by theclamping members of the first substrate clamping mechanism and thesecond substrate clamping mechanism when the substrate clamping state isswitched between the first clamping state and the second clamping state.

According to further another aspect of the present invention, there isprovided a substrate treatment apparatus, which comprises: a substraterotating member which is rotated about a rotary shaft thereof whileholding a substrate; a plurality of clamping members attached to thesubstrate rotating member, and operative in a substrate clamping statefor clamping the substrate and in a substrate unclamping state forunclamping the substrate; and a link mechanism for associating substrateclamping/unclamping motions of the plural clamping members with rotationof the substrate rotating member; wherein the link mechanism comprises acam member having a cam surface undulated parallel to the rotary shaftand configured as circularly surrounding the rotary shaft of thesubstrate rotating member, and a movement converting mechanism attachedto the substrate rotating member and including a cam follower whichmoves generally parallel to the rotary shaft while traveling along thecam surface of the cam member in abutment against the cam surface inassociation with relative rotation of the cam member with respect to thesubstrate rotating member, whereby movement of the cam follower isconverted into the substrate clamping/unclamping motions of the pluralclamping members.

With this arrangement, when the substrate rotating member is rotatedabout the rotary shaft, the cam follower circularly travels along thecam surface of the cam member in association with the relative rotationof the cam member with respect to the substrate rotating member. As aresult, the cam follower moves parallel to the rotary shaft. Themovement of the cam follower is converted into the motions of the pluralclamping members attached to the substrate rotating member. This simpleconstruction permits the clamping members to clamp and unclamp thesubstrate, while the substrate is rotated.

The plural clamping members may simultaneously be operative in thesubstrate clamping state and in the substrate unclamping state. Wherethe rotation of the substrate rotating member is accelerated ordecelerated with all the clamping members kept in the substrateunclamping state, for example, the substrate is rotated relative to thesubstrate rotating member. Thus, the clamping members can changesubstrate clamping positions.

However, this arrangement entails abrasion of the clamping members dueto sliding contact between the clamping members and the substrate.Therefore, the relative rotation of the substrate with respect to thesubstrate rotating member is preferably prevented.

A relationship between the cam surface and the cam follower ispreferably defined so that at least one pair of clamping members out ofthe plural clamping members undergo the substrate clamping/unclampingmotions with a timing offset.

With this arrangement, the at least one pair of clamping members out ofthe plural clamping members undergo the substrate clamping/unclampingmotions with a timing offset. Therefore, some of the clamping memberscan be retracted from a peripheral surface of the substrate, while thesubstrate is clamped by the other clamping members. Hence, the entireperipheral surface and peripheral edge portion of the substrate canproperly be treated with a treatment fluid (a treatment liquid or atreatment gas) by sequentially retracting the plural clamping membersfrom the peripheral surface. In addition, there is no need for rotatingthe substrate relative to the substrate rotating member, so that theabrasion of the clamping members can be suppressed.

Further, the clamping members may be operative so that the substrate isconstantly clamped by some of the clamping members. Thus, the substratecan constantly stably be held during the rotation of the substrate.Where the treatment of a surface of the substrate is performed with ashield plate located adjacent the substrate surface, for example, aspacing between the shield plate and the substrate surface canconstantly strictly be controlled. Thus, the quality of the treatment ofthe substrate can be improved.

Further, the substrate is constantly clamped by some of the clampingmembers for prevention of the relative rotation of the substrate withrespect to the substrate rotating member during the rotation of thesubstrate, whereby the rotational position of the substrate can easilybe controlled.

The substrate treatment apparatus preferably further comprises a modeswitching mechanism for switching an operation mode of the linkmechanism between an active mode and an inactive mode by changing adistance between the substrate rotating member and the cam surface ofthe cam member as measured along the rotary shaft.

With this arrangement, the distance between the substrate rotatingmember and the cam surface of the cam member is changed to bring the camfollower and the cam surface into non-contact relation, to permit thecam follower to travel along the cam surface so as to bring the clampingmembers into the substrate clamping state and into the substrateunclamping state, or to bring the substrate rotating member and the camsurface into close relation so as to constantly keep the clampingmembers in the substrate unclamping state. In this manner, the operationmode of the link mechanism can be switched between the active mode inwhich the substrate clamping/unclamping motions of the clamping membersare associated with the rotation of the substrate rotating member andthe inactive mode in which the substrate clamping/unclamping motions arenot associated with the rotation of the substrate rotating member.

When the substrate is to be loaded onto or unloaded from the substraterotating member, for example, the clamping members are preferably keptin the substrate unclamping state irrespective of the rotationalposition of the substrate rotating member. Therefore, the operation modeis switched to the inactive mode. Particularly, when the peripheral edgeportion of the substrate held by the substrate rotating member istreated with the treatment fluid, the operation mode of the linkmechanism is preferably switched to the active mode to bring theclamping members into the substrate clamping state and into thesubstrate unclamping state. When the substrate is rotated at a highrotation speed to spin off the treatment liquid from the substratesurface for drying the substrate after the treatment of the substratewith the treatment liquid, the operation mode of the link mechanism ispreferably switched to the inactive mode to keep the clamping members inthe substrate clamping state.

According to still another aspect of the present invention, there isprovided a substrate treatment apparatus, which comprises: a substraterotating member which are rotated while holding a substrate; a pluralityof clamping members attached to the substrate rotating member, andoperative in a substrate clamping state for clamping the substrate andin a substrate unclamping state for unclamping the substrate; a linkmechanism for associating substrate clamping/unclamping motions of theplural clamping members with rotation of the substrate rotating member,and causing at least one pair of clamping members out of the pluralclamping members to undergo the substrate clamping/unclamping motionswith a timing offset; and a mode switching mechanism for switching anoperation mode of the link mechanism between an active mode and aninactive mode.

The mode switching mechanism is preferably adapted to switch theoperation mode of the link mechanism between the active mode in whichthe plural clamping members are brought into the substrate clampingstate and into the substrate unclamping state in association with therotation of the substrate rotating member and the inactive mode in whichthe plural clamping members are kept in the substrate clamping state.

With this arrangement, the clamping members undergo the substrateclamping/unclamping motions in the active mode, and are kept in thesubstrate clamping state in the inactive mode. When a peripheral edgeportion of the substrate is treated by supplying a treatment fluid, forexample, the operation mode is switched to the active mode. When thetreatment liquid is spun off from a surface of the substrate for dryingthe substrate, the operation mode is switched to the inactive mode.Thus, the peripheral edge portion of the substrate can properly betreated and, in addition, the substrate can stably be held in the dryingprocess.

The mode switching mechanism may be adapted to switch the operation modeof the link mechanism among the active mode in which the plural clampingmembers are brought into the substrate clamping state and into thesubstrate unclamping state in association with the rotation of thesubstrate rotating member, a first inactive mode in which the pluralclamping members are kept in the substrate clamping state, and a secondinactive mode in which the plural clamping members are kept in thesubstrate unclamping state.

With this arrangement, when the substrate is treated by supplying thetreatment fluid, the operation mode is switched to the active mode. Whenthe rotation of the substrate rotating member is accelerated ordecelerated, or when the substrate rotating member is rotated at a highspeed for removal of the treatment liquid from the substrate surface,the operation mode is switched to the first inactive mode. Further, whenthe substrate is rotated relative to the substrate rotating member, orwhen the substrate is loaded onto or unloaded from the substraterotating member, the operation mode is switched to the second inactivemode.

In the active mode, the substrate clamping state preferably includes afirst substrate clamping state where the substrate is clamped by some ofthe plural clamping members, a second substrate clamping state where thesubstrate is clamped by the other clamping members, and an intermediateclamping state where the substrate is clamped by all the plural clampingmembers when the substrate clamping state is switched between the firstsubstrate clamping state and the second substrate clamping state.

With this arrangement, the substrate clamping state is switched betweenthe first substrate clamping state where the substrate is clamped bysome of the plural clamping members and the second substrate clampingstate where the substrate is clamped by the other clamping members inthe active mode. Thus, when the peripheral edge portion of the substrateis treated with the treatment fluid, for example, the treatment fluidcan properly be supplied to the entire peripheral edge portion of thesubstrate. Further, the substrate clamping state is once switched to theintermediate clamping state where the substrate is clamped by all theplural clamping members, when being switched between the first substrateclamping state and the second substrate clamping state. Hence, there isno possibility that the substrate is unstably held during the switchingof the substrate clamping state of the clamping members. When thetreatment of the substrate surface is performed with a shield platelocated adjacent the substrate surface, for example, a spacing betweenthe shield plate and the substrate can constantly stably be kept duringthe treatment of the substrate. The intermediate clamping state canassuredly prevent the relative rotation of the substrate with respect tothe substrate rotating member. Therefore, the abrasion of the clampingmembers due to the relative rotation can be suppressed.

The link mechanism preferably comprises a cycle changing mechanism forchanging a substrate clamping/unclamping cycle of the plural clampingmembers in the active mode.

With this arrangement, the substrate clamping/unclamping cycle of theclamping members can be changed, so that the substrateclamping/unclamping motions of the clamping members can be caused at aspeed such as not to adversely affect the treatment of the peripheraledge portion of the substrate with the treatment fluid.

Where a cam member having a cam surface rotatable about a rotary shaftas described above and a cam rotative drive mechanism for rotativelydriving the cam member for the rotation of the cam surface about therotary shaft are provided, for example, the cycle changing mechanism maycomprise a cam rotation controlling mechanism for controlling the camrotative drive mechanism to variably control the rotation speed of thecam member.

The substrate treatment apparatus preferably further comprises anetching liquid supply mechanism for supplying an etching liquid to theperipheral edge portion of the substrate held by the substrate rotatingmember.

With this arrangement, the peripheral edge portion of the substrate canbe subjected to an etching process or a cleaning process.

According to further another aspect of the present invention, there isprovided a substrate treatment method, which comprises the steps of:rotating a substrate while holding the substrate by a substrate rotatingmember; associating substrate clamping/unclamping motions of a pluralityof clamping members attached to the substrate rotating member withrotation of the substrate rotating member, and causing at least one pairof clamping members out of the plural clamping members to undergo thesubstrate clamping/unclamping motions with a timing offset; andswitching an operation mode between an active mode in which thesubstrate clamping/unclamping motions of the plural clamping members areassociated with the rotation of the substrate rotating member and aninactive mode in which the substrate clamping/unclamping motions are notassociated with the rotation of the substrate rotating member.

The foregoing and other objects, features and effects of the presentinvention will become more apparent from the following description ofthe preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram for explaining the construction of asubstrate treatment apparatus according to one embodiment of the presentinvention;

FIG. 2 is a plan view of a spin chuck provided in the substratetreatment apparatus;

FIG. 3 is a plan view for explaining the arrangement of movementconverting mechanisms provided in a spin base of the spin chuck;

FIG. 4 is a sectional view (taken along a line IV-IV in FIG. 5) forexplaining a construction associated with the spin chuck;

FIG. 5 is a plan view for explaining the construction of a drivemechanism for driving clamping members;

FIG. 6 is a plan view for explaining the constructions of first andsecond non-rotative movable members driven by the drive mechanism;

FIG. 7 is a perspective view for explaining the construction of themovement converting mechanism for converting a driving force transmittedfrom the first non-rotative movable member into the movements of theclamping members;

FIG. 8 is a perspective view for explaining the construction of anotherportion of the movement converting mechanism;

FIG. 9 is a block diagram for explaining the electrical construction ofthe substrate treatment apparatus;

FIG. 10 is a plan view of a spin chuck provided in a substrate treatmentapparatus according to a second embodiment of the present invention;

FIG. 11 is a perspective view illustrating the common construction ofclamping members according to the second embodiment;

FIG. 12( a) is a partial sectional view illustrating an arrangement fortransmitting a driving force between a first rotative movable member anda lift member for one clamping member according to the secondembodiment;

FIG. 12( b) is a partial sectional view illustrating an arrangement fortransmitting a driving force between a second rotative movable memberand a lift member for another clamping member according to the secondembodiment;

FIGS. 13( a) to 13(i) are schematic diagrams illustrating wafer clampingstates according to the second embodiment;

FIG. 14 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a third embodiment of thepresent invention;

FIG. 15 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a fourth embodiment of thepresent invention;

FIG. 16 is a sectional view for explaining a modification of the fourthembodiment;

FIG. 17 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a fifth embodiment of thepresent invention;

FIG. 18 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a sixth embodiment of thepresent invention;

FIG. 19 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a seventh embodiment of thepresent invention;

FIG. 20 is a sectional view illustrating major portions of the substratetreatment apparatus of FIG. 19 on a greater scale;

FIG. 21 is a plan view illustrating the internal construction of a spinchuck employed in a substrate treatment apparatus according to an eighthembodiment of the present invention;

FIG. 22 is a perspective view illustrating the construction of aclamping member employed in a substrate treatment apparatus according toa ninth embodiment of the present invention;

FIG. 23 is a schematic sectional view for explaining the construction ofa substrate treatment apparatus according to a tenth embodiment of thepresent invention;

FIGS. 24(A) and 24(B) are diagrams for explaining the configuration of acam face;

FIGS. 25(A), 25(B) and 25(C) are plan views illustrating modificationsof the configuration of the cam face; and

FIGS. 26(A) and 26(B) are plan views illustrating modified clampingmembers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a schematic diagram for explaining the construction of asubstrate treatment apparatus according to one embodiment of the presentinvention. The substrate treatment apparatus is capable of treating asemiconductor wafer W as a generally round substrate (hereinafterreferred to simply as “wafer”) formed with a thin film forsimultaneously removing portions of the thin film present on a rearsurface of the wafer W, a peripheral edge portion of a front surface ofthe wafer W and a peripheral surface of the wafer W. The substratetreatment apparatus includes a spin chuck 1 provided in a treatment cup(not shown) for horizontally holding the wafer W with the rear surfaceof the wafer W facing downward and rotating the wafer W thus held aboutan axis vertically extending through a center portion of the wafer W.

The spin chuck 1 is coupled to a rotation shaft (drive shaft) of a motor2 as a rotative drive mechanism for rotation thereof. The rotation shafthas a hollow inside in which a treatment liquid supply pipe 3 isinserted for supplying deionized water or an etching liquid. Thetreatment liquid supply pipe 3 is connected to a center nozzle (fixednozzle) having an outlet port which is located adjacent the center ofthe lower surface of the wafer W held by the spin chuck 1. Therefore,the etching liquid or deionized water can be supplied toward the lowersurface of the wafer W from the outlet port of the center nozzle.

The etching liquid or deionized water is supplied to the treatmentliquid supply pipe 3 through a deionized water supply valve 4 connectedto a deionized water supply source or through an etching liquid supplyvalve 5 connected to an etching liquid supply source when required.

The etching liquid to be employed is determined depending on the type ofthe thin film to be removed from the surface (the upper or lowersurface) of the wafer W. Where a metal film such as a thin copper filmis removed from the lower surface of the wafer W, for example, a mixtureof hydrochloric acid and hydrogen peroxide aqueous solution, a mixtureof hydrofluoric acid and hydrogen peroxide aqueous solution or a mixtureof hydrofluoric acid and nitric acid is used as the etching liquid.Where a polysilicon film, an amorphous silicon film or a silicon oxidefilm is removed from the wafer W, for example, a mixture of hydrofluoricacid and nitric acid is used as the etching liquid. Where an oxide filmis removed from the wafer W, for example, dilute hydrofluoric acid isused as the etching liquid.

Though not shown, a scan nozzle may further be provided, which isreciprocally movable between an upper position above the wafer W and aretracted position apart from the upper position for supplying theetching liquid or deionized water toward the upper surface of the waferW. The scan nozzle is used for treatment of the entire upper surface ofthe wafer W.

A disk-shaped shield plate 6 is horizontally disposed above the spinchuck 1 in opposed relation to the wafer W held by the spin chuck 1. Theshield plate 6 is dimensioned so as to cover substantially the entireupper surface of the wafer W, and is attached to a distal end portion ofan arm 8 coupled to a lift drive mechanism 7 rotatably about a verticalaxis.

The shield plate 6 can be moved up and down with respect to the spinchuck 1 by the lift drive mechanism 7. Further, the shield plate 6 canbe rotated about a rotation axis thereof aligned with the rotation axisof the spin chuck 1 by a rotative drive mechanism 9. Nitrogen gas as aninert gas can be supplied to a space between the shield plate 6 and thewafer W. Nitrogen gas is introduced from a nitrogen gas supply valve 10through a nitrogen gas supply pipe 11 to a nitrogen gas outlet port (notshown) provided in a center portion of a lower surface of the shieldplate 6. As required, deionized water supplied from a deionized watersupply valve 12 or any other treatment liquid may be supplied to theupper surface of the wafer W from a nozzle provided at the center of thelower surface of the shield plate 6.

FIG. 2 is a plane view of the spin chuck 1. The spin chuck 1 includes adisk-shaped spin base 21 and a plurality of clamping members (sixclamping members F1 to F3 and S1 to S3 in this embodiment) generallyequiangularly disposed in a peripheral edge portion of the spin base 21on an upper surface of the spin base 21. Of these clamping members,three alternate clamping members F1 to F3 circumferentially disposedconstitute a first clamping member set, and are operatively associatedwith each other to clamp and unclamp the wafer W. The other threeclamping members S1 to S3 constitute a second clamping member set, andare operatively associated with each other to clamp and unclamp thewafer W.

The clamping members F1 to F3 of the first clamping member set (firstsubstrate clamping mechanism) are operable independently of the clampingmembers S1 to S3 of the second clamping member set (second substrateclamping mechanism). That is, when the clamping members F1 to F3 clampthe wafer W at circumferential positions of the wafer W spaced at anangular interval of about 120 degrees, the clamping members S1 to S3 mayunclamp the wafer W. Alternatively, the clamping members S1 to S3 mayclamp the wafer W in abutment against three circumferential positions ofthe wafer W spaced at an angular interval of about 120 degrees, when theclamping members F1 to F3 unclamp the wafer W. Further, the wafer W maybe clamped by all the clamping members F1 to F3 and S1 to S3. In thiscase, the wafer W is clamped at six circumferential positions of thewafer W spaced at an angular interval of about 60 degrees.

FIG. 3 is a plan view for explaining the arrangement of movementconverting mechanisms provided in the spin base 21. The spin base 21includes a first movement converting mechanism FT1 for operating theclamping members F1, F2, F3 in association with each other, and a secondmovement converting mechanism FT2 for operating the clamping members S1,S2, S3 in association with each other. The movement converting mechanismFT1 includes link mechanisms 31, 32 and 33 for operating the clampingmembers F1, F2 and F3, respectively, and a first link ring 34 forlinking the link mechanisms 31 to 33. Similarly, the second movementconverting mechanism FT2 includes link mechanisms 41, 42 and 43 foroperating the clamping members S1, S2 and S3, respectively, and a secondlink ring 44 for linking the link mechanisms 41 to 43.

The first link ring 34 and the second link ring 44 are generally annularmembers disposed coaxially with a rotation axis of the spin base 21. Thesecond link ring 44 is disposed outwardly of the first link ring 34. Thefirst and second link rings 34, 44 are movable up and down along therotation axis of the spin base 21. The clamping members F1 to F3 can beoperated by moving up and down the first link ring 34, while theclamping members S1 to S3 can be operated by moving up and down thesecond link ring 44.

FIG. 4 is a sectional view (taken along a line IV-IV in FIG. 5) forexplaining a construction associated with the spin chuck 1. The spinbase 21 includes an upper plate 22 and a lower plate 23 fixed to eachother by bolts. A space for accommodating the first and second movementconverting mechanisms FT1, FT2 is defined between the upper plate 22 andthe lower plate 23. A through-hole 24 is formed in center portions ofthe upper and lower plates 22, 23 as extending through the spin base 21.The treatment liquid supply pipe 3 extends through the through-hole 24and further through a rotary shaft 25 of the spin chuck 1. The centernozzle 26, which has the outlet port 26 a to be opposed to the center ofthe lower surface of the wafer W held by the spin chuck 1, is fixed toan upper end of the treatment liquid supply pipe 3.

The rotary shaft 25 is unitary with the drive shaft of the motor 2 andextends through the motor 2. The motor 2 is surrounded by a casing 27,which is further surrounded by a cylindrical cover member 28. The covermember 28 has an upper edge located in the vicinity of a lower surfaceof the spin base 21, and a seal mechanism 29 is provided on an interiorsurface portion of the cover member 28 adjacent to the upper edge of thecover member 28. The seal mechanism 29 is kept in sliding contact with aseal member 30 fixed to the lower surface of the spin base 21, and amechanical member accommodating space 50 is defined between the sealmechanism 29 and the rotary shaft 25 as being isolated from an externalenvironment.

In the mechanical member accommodating space 50, a generally annulargear case 51 is attached to an upper cover 27 a of the casing 27 assurrounding the rotary shaft 25. A first motor M1 and a second motor M2are fixed onto the gear case 51 in symmetrical relation about the rotaryshaft 25 as shown in plan in FIG. 5.

As shown in FIG. 4, bearings 52 and 53 are respectively press-fitted oninterior surfaces of inner and outer peripheral walls of the gear case51. The bearings 52, 53 are disposed coaxially with the rotary shaft 25.A first ring-shaped gear 54 is fixed to a rotary ring of the innerbearing 52 as surrounding the rotary shaft 25, while a secondring-shaped gear 55 is fixed to a rotary ring of the outer bearing 53 assurrounding the rotary shaft 25. Therefore, the first gear 54 and thesecond gear 55 are rotatable coaxially about the rotary shaft 25 in thegear case 51, and the second gear 55 is disposed outwardly of the firstgear 54. The first gear 54 has gear teeth provided on an outerperipheral surface thereof, while the second gear 55 has gear teethprovided on an inner peripheral surface thereof.

A pinion 56 fixed to a drive shaft of the first motor M1 is disposedbetween the first gear 54 and the second gear 55, and meshed with thefirst gear 54 disposed inwardly thereof. Similarly, a pinion 57 fixed toa drive shaft of the second motor M2 is disposed between the first gear54 and the second gear 55, and meshed with the second gear 55 disposedoutwardly thereof as shown in FIG. 5.

A pair of first ball thread mechanisms 61, 61 are disposed in opposedrelation with the rotary shaft 25 interposed therebetween (i.e.,laterally of the rotary shaft 25) apart from the motors M1, M2 on thegear case 51. Further, a pair of second ball thread mechanisms 62, 62are disposed in opposed relation with the rotary shaft 25 interposedtherebetween (i.e., laterally of the rotary shaft 25) apart from themotors M1, M2 and the first ball thread mechanisms 61, 61 on the gearcase 51.

As shown in FIG. 4, the first ball thread mechanisms 61, 61 each includea thread shaft 63 disposed parallel to the rotary shaft 25 and a ballnut 64 threadingly engaged with the thread shaft 63. The thread shaft 63is attached to an upper cover of the gear case 51 via a bearing 65, anda lower end portion thereof extends into the gear case 51. A gear 66 isfixed to the lower end of the thread shaft 63. The gear 66 is disposedbetween the first gear 54 and the second gear 55, and meshed with thefirst gear 54 disposed inwardly thereof.

On the other hand, a first non-rotative movable member 68 is attached tothe ball nut 64. The first non-rotative movable member 68 is an annularmember surrounding the rotary shaft 25, and a stationary ring 71 f of afirst bearing 71 disposed around the rotary shaft 25 is fixed to aninner peripheral surface of the first non-rotative movable member 68. Arotary ring 71 r of the first bearing 71 is disposed inwardly of thestationary ring 71 f around the rotary shaft 25. The rotary ring 71 r isfixed to an outer peripheral surface of a first annular rotative movablemember 81 surrounding the rotary shaft 25. The first rotative movablemember 81 is engaged with guide rails 91 projecting from an outerperipheral surface of the rotary shaft 25. The guide rails 91 extendparallel to the rotary shaft 25. Therefore, the first rotative movablemember 81 is coupled to the rotary shaft 25 so as to be guidedly movablealong the rotary shaft 25.

When the first motor M1 is driven to rotate the pinion 56, the rotationof the pinion 56 is transmitted to the first gear 54. Thus, the gears 66each meshed with the first gear 54 are rotated to rotate the threadshafts 63 of the ball thread mechanisms 61, 61. Thus, the ball nuts 64and the first non-rotative movable member 68 coupled to the ball nuts 64are moved up and down along the rotary shaft 25. The first rotativemovable member 81 to be rotated together with the rotary shaft 25 iscoupled to the first non-rotative movable member 68 via the bearing 71.Therefore, the first rotative movable member 81 can be moved up and downalong the guide rails 91 by the up and down movement of the firstnon-rotative movable member 68 even during the rotation of the rotaryshaft 25.

As shown in FIG. 6, a second ring-shaped non-rotative movable member 78is disposed outwardly of the first ring-shaped non-rotative movablemember 68 which is moved up and down by the first ball thread mechanisms61, 61. The first non-rotative movable member 68 has a pair ofprojections 69, 69 respectively projecting radially outwardly inassociation with the ball nuts 64 of the pair of first ball threadmechanisms 61, 61, and another pair of projections 70, 70 respectivelyprojecting radially outwardly from positions thereof circumferentiallyoffset from the projections 69, 69. Guide shafts 67, 67 extending alongthe rotary shaft 25 are respectively coupled to the projections 70, 70.The guide shafts 67, 67 are vertically guided along the rotary shaft 25.Thus, the first non-rotative movable member 68 is movable up and downalong the rotary shaft 25, while being kept horizontally.

On the other hand, the second ring-shaped non-rotative movable member 78has a pair of projections 79, 79 respectively projecting radiallyinwardly in association with the second ball thread mechanisms 62, 62.The second ball thread mechanisms 62, 62 each have substantially thesame construction as the first ball thread mechanism 61, except that agear provided at a lower end of a thread shaft thereof is inwardlymeshed with the second gear 55 between the first gear 54 and the secondgear 55 within the gear case 51. Therefore, ball nuts of the second ballthread mechanisms 62, 62 can be moved up and down by driving the pinion57 meshed with the second gear 55 by the second motor M2. These ballnuts are coupled to the projections 79, 79 of the second non-rotativemovable member 78.

The second non-rotative movable member 78 further has another pair ofprojections 80, 80 respectively projecting radially inwardly frompositions thereof circumferentially offset from the projections 79, 79.Guide shafts 77, 77 are respectively coupled to the projections 80, 80.The guide shafts 77, 77 are vertically guided along the rotary shaft 25.Thus, the second non-rotative movable member 78 is vertically movable upand down along the rotary shaft 25, while being kept horizontally.

As shown in FIG. 4, a stationary ring 72 f of a second bearing 72surrounding the rotary shaft 25 is fixed to an outer peripheral surfaceof the second non-rotative movable member 78. A rotary ring 72 r of thesecond bearing 72 is fixed to an inner peripheral surface of a secondring-shaped rotative movable member 82 surrounding the rotary shaft 25.Guide pins 92 are implanted in the second rotative movable member 82 asvertically projecting from an upper surface of the second rotativemovable member 82 along the rotary shaft 25.

When the second non-rotative movable member 78 is moved up and downtogether with the nuts of the second ball thread mechanisms 62, 62, thesecond rotative movable member 82 coupled to the second bearing 72 ismoved up and down simultaneously with the second non-rotative movablemember 78. As will be described later, the second rotative movablemember 82 is rotated together with the spin base 21 (i.e., together withthe rotary shaft 25). Even during the rotation of the second rotativemovable member 82, the second rotative movable member 82 can be moved upand down by driving forces received from the second ball threadmechanisms 62.

FIG. 7 is a perspective view for explaining the construction of the linkmechanism 31 of the first movement converting mechanism FT1. Theclamping member F1 is fixed to an upper end of a rotatable verticalshaft 35, and includes a plate portion 95 having a generally wedge shapeas seen in plan and an abutment portion 96 (substrate clamp pin)provided upright on the plate portion 95 apart from a rotation axis ofthe shaft 35 so as to be brought into opposed relation to the peripheralsurface of the wafer W. A wafer support portion 95 a projects from arotation center of the plate portion 95. The wafer support portion 95 ais located in association with a lower surface portion of the wafer Wslightly inwardly spaced from the peripheral edge of the wafer W tosupport a peripheral edge portion of the lower surface of the wafer Wfrom a lower side.

A lever 36 is fixed to the shaft 35 as projecting laterally below theclamping member F1, and a pin 36 a is provided on an end portion of thelever 36 as extending vertically upward. The link mechanism 31 includesthe lever 36, a rocking plate 37 having an elongate hole 37 a engagedwith the lever 36, a crank member 38 coupled to the rocking plate 37, alever 39 having a bearing member 39 a supporting a shaft 38 a of thecrank member 38 pivotally about an axis thereof, a crank member 40coupled to the lever 39, a bearing member 45 pivotally supporting ashaft 40 a of the crank member 40, and a lift member 46 having anelongate hole 46 a engaged with a shaft 40 b of the crank member 40. Alower end of the lift member 46 is connected to an upper surface of thefirst link ring 34. The first link ring 34 is disposed in engagementwith an outer circumferential shoulder 81 a of the first rotativemovable member 81.

As shown in FIG. 4, a plurality of guide shafts 47 (three guide shaftsin this embodiment) are equiangularly provided on the upper surface ofthe first link ring 34 as extending vertically upward along the rotaryshaft 25. The guide shafts 47 extend through the lower plate 23 of thespin base 21, and are held in an upwardly and downwardly movable mannerby bushes 48 provided within the spin base 21.

Therefore, the first link ring 34 is movable up and down along therotary shaft 25 together with the first rotative movable member 81,while being kept horizontally. As the lift member 46 is correspondinglymoved up and down, the crank member 40 is rotated about the shaft 40 asupported by the bearing member 45. The elongate hole 46 a formed in thelift member 46 extends horizontally, so that the up and down movement ofthe lift member 46 is smoothly converted into a pivotal movement of thecrank member 40.

The pivotal movement of the crank member 40 pivots the lever 39, so thatthe crank member 38 supported by the bearing member 39 a of the lever 39is moved circumferentially of the spin base 21 as seen in plan. Theelongate hole 37 a formed in the rocking plate 37 extends radially ofthe spin base 21, and the pin 36 a is vertically engaged with theelongate hole 37 a. Therefore, the rocking plate 37 is rocked slightlyup and down with respect to the spin base 21, while being kepthorizontally. Since the pin 36 a is moved circumferentially of the spinbase 21 by the rocking of the rocking plate 37, the clamping member F1is pivoted about the shaft 35 by the lever 36. Thus, the link mechanism31 converts the up and down movement of the first rotative movablemember 81 into the pivotal movement of the clamping member F1.

The link mechanisms 32, 33 each have the same construction as the linkmechanism 31. These link mechanisms 31, 32, 33 are operative inassociation with each other by the operation of the first link ring 34.

The link mechanisms 41, 42, 43 for the clamping members S1, S2, S3 eachhave substantially the same construction as the link mechanism 31 and,therefore, no explanation will be given thereto. However, the secondlink ring 44 is disposed radially outwardly of the first link ring 34around the spin base 21. Therefore, the shaft 40 a of the crank member40 of the link mechanism 41 to 43 has a smaller length than that of thelink mechanism 31, so that the bearing member 45 is correspondinglyslightly different in structure. In FIG. 3, a reference numeral 49denotes guide shafts provided upright on the second link ring 44. Theguide shafts 49 have the same function as the guide shafts 47 providedupright on the first link ring 34, and are coupled to the spin base 21in an upwardly and downwardly movable manner like the guide shafts 47.

As shown in FIG. 4, a compression coil spring 58 is wound around thelift member 46 of each of the link mechanisms 31, 32, 33 between a lowersurface of the lower plate 23 of the spin base 21 and the upper surfaceof the first link ring 34. Thus, the first link ring 34 is biaseddownward. As a result, the clamping member F1 is biased in a closingdirection with the abutment portion 96 thereof directing inwardlyradially of the spin base 21.

Similarly, a compression coil spring 59 is wound around the lift member46 of each of the link mechanisms 41, 42, 43 between the lower surfaceof the lower plate 23 of the spin base 21 and an upper surface of thesecond link ring 44. Therefore, the clamping members F1, F2, F3, S1, S2,S3 are each biased in a closing direction with the abutment portions 96thereof directing inwardly radially of the spin base 21. Where the ballnuts 64 of the first and second ball thread mechanisms 61, 62 aresufficiently lowered, the wafer W is clamped by the clamping members F1to F3 and S1 to S3 by spring forces of the compression coil springs 58,59. Since the wafer W is resiliently clamped by utilizing the resilientforces of the compression coil springs 58, 59, a damage to the wafer Wcan advantageously be suppressed.

As shown in FIG. 3, sensor sections 97, 98 for detecting the heights ofthe first link ring 34 and the second link ring 44, respectively, areprovided for detection of a wafer clamping state effected by theclamping members F1 to F3 and S1 to S3. For example, the sensor sections97, 98 each have three sensors. These sensors are capable of detectingthe first link ring 34 and the second link ring 44 at a first heightwhich corresponds to a state where the abutment portions 96 of theclamping members F1 to F3, S1 to S3 are retracted from the peripheralsurface of the wafer W, at a second height which corresponds to a statewhere the clamping members F1 to F3, S1 to S3 clamp the wafer W inabutment against the peripheral surface of the wafer W, and at a thirdheight which corresponds to a state where the abutment portions 96 ofthe clamping members F1 to F3, S1 to S3 are located inwardly of a waferperipheral surface position radially of the spin base 21 in the absenceof the wafer W on the spin base 21. The first height is the highest, andthe second height is the second highest. The third height is the lowest.

The wafer clamping state and wafer unclamping state of the clampingmembers F1 to F3 and S1 to S3 and the absence of the wafer W on the spinbase 21 are detected on the basis of outputs from the sensor sections97, 98.

Sensors for detecting the heights of the first and second non-rotativemovable members 68, 78 may additionally be provided to check if thefirst and second link rings 34, 44 are moved up and down in associationwith the up and down movements of the ball nuts 64 of the first andsecond ball thread mechanisms 61, 62.

FIG. 8 is an exploded perspective view illustrating an arrangement forcoupling the second link ring 44 and the lift member 46 of the linkmechanism 41, 42, 43. The three lift members 46 are provided upright onthe upper surface of the second link ring 44 in 120-degree spacedrelation. Two stepped through-holes 94 are formed at positions offsetfrom the lift members 46 in 180-degree spaced relation on the uppersurface of the second link ring 44. Bushes 93 are respectively fitted inthe through-holes 94. The guide pins 92 provided upright on the uppersurface of the second rotative movable member 82 are respectivelyinserted through the bushes 93. The guide pins 92 are fixed to thesecond rotative movable member 82 with lower thread portions 92 athereof threadingly engaged with threaded holes 82 a formed in the uppersurface of the second rotative movable member 82.

Thus, the guide pins 92 are respectively engaged with the bushes 93,whereby the rotation of the second rotative movable member 82 relativeto the second link ring 44 and the lift members 46 (for the linkmechanisms 41, 42, 43) is prevented.

Therefore, the lift members 46, the second link ring 44 and the secondrotative movable member 82 are moved up and down along the rotary shaft25 without relative rotation thereof even during the co-rotation withthe spin base 21, when the second non-rotative movable member 78 ismoved up and down by the second ball thread mechanisms 62.

In this embodiment, the clamping members F1 to F3 and S1 to S3 arecomposed of an electrically conductive resin (e.g., an electricallyconductive PEEK (polyetheretherketone), and components of the first andsecond movement converting mechanisms FT1, FT2 are composed of anelectrically conductive resin or a metal (e.g., stainless steel (SUS) orthe like). Further, the lower plate 23 of the spin base 21 is composedof an electrically conductive material (e.g., SiC or aluminum). Therotary shaft 25 connected to the lower plate 23 is composed of a metalsuch as SUS, and the casing (metal casing) of the motor 2 is grounded.

With this arrangement, a grounding path is established, which extendsfrom the clamping members F1 to F3 and S1 to S3 to the casing of themotor 2 through the first and second movement converting mechanisms FT1,FT2, the lower plate 23 and the rotary shaft 25. Thus, electrostaticcharges occurring due to friction between the wafer W and the treatmentliquid (etching liquid or deionized water) supplied to the surface ofthe wafer W can be released, whereby an electrostatic discharge damageto a device formed in the wafer W can be prevented.

Since the removal of the electrostatic charges from the wafer W can beachieved by utilizing the driving mechanisms for the clamping members F1to F3 and S1 to S3 during a spinning process, easier design and costreduction can be realized without the need for additionally providing anelectrostatic charge remover of discharge type or X-ray type. Where thedischarge type electrostatic charge remover is employed, generation ofmetal particles is problematic. Where the X-ray type electrostaticcharge remover is employed, X-ray safeguards are problematic. Incontrast, the arrangement according to the present invention is freefrom these problems.

FIG. 9 is a block diagram for explaining the electrical construction ofthe substrate treatment apparatus. A control section 100 including amicroprocessor and the like controls the first and second motors M1, M2,the motor 2 for rotating the spin chuck 1, the rotative drive mechanism9 and the lift drive mechanism 7. The control section 100 furthercontrols the opening and closing of the nitrogen gas supply valve 10,the deionized water supply valve 12, the deionized water supply valve 4and the etching liquid supply valve 5.

When a wafer W is loaded onto the spin chuck 1 by a substrate transportrobot not shown, the motor 2 and the rotative drive mechanism 9 are keptin halt under the control of the control section 100. Further, thecontrol section 100 controls the lift drive mechanism 7 to move theshield plate 6 to a retracted position above the spin chuck 1, and thevalves 10, 12, 4, 5 are kept closed under the control of the controlsection 100.

The control section 100 controls the first and second motors M1, M2 tomove the first and second link rings 34, 44 to an upper position (at thefirst height). Thus, the clamping members F1 to F3 and S1 to S3 areopened with the abutment portions 96 retracted radially outwardly of thespin base 21. In this sate, the substrate transport robot places thewafer W on the wafer support portions 95 a of the plate portions 95 ofthe clamping members F1 to F3 and S1 to S3.

In this state, the control section 100 controls, for example, the firstmotor M1 to drive the first ball thread mechanisms 61 so as to lower theball nuts 64. Thus, the first rotative movable member 81 is lowered,whereby the first link ring 34 is moved down and the lift members 46 aremoved down by the spring forces of the compression coil springs 58 andthe gravity. As a result, the clamping members F1 to F3 are pivoted, sothat the abutment portions 96 thereof are brought into abutment againstthe peripheral surface of the wafer W. Thus, the wafer W is clamped bythe clamping members F1 to F3. At this time, the clamping members S1 toS3 are kept open (with the abutment portions 96 thereof retracted fromthe peripheral surface of the wafer W), because the electric motor M2 isnot driven.

Thereafter, the control section 100 energizes the motor 2 to rotate thespin chuck 1 (first substrate rotation step, rotation step, andsubstrate clamping/rotating step). At the same time, the lift drivemechanism 7 is controlled to lower the shield plate 6 to the vicinity ofthe wafer W, and then the rotative drive mechanism 9 is energized torotate the shield plate 6 in synchronization with the spin chuck 1.

Subsequently, the control section 100 opens the etching liquid supplyvalve 5 and the nitrogen gas supply valve 10. Thus, the etching liquidis supplied toward the center of the lower surface of the wafer W fromthe center nozzle 26 (treatment liquid supply step, treatment fluidsupply step, etching liquid supply step). The etching liquid flowsradially outwardly over the lower surface of the wafer W and then overthe peripheral surface of the wafer W onto the upper surface of thewafer W. The amount of the etching liquid flowing onto the upper surfaceof the wafer W is controlled by ejecting nitrogen gas from the center ofthe shield plate 6. As a result, an etching process is performed to etchthe entire rear surface of the wafer W, to etch away an unnecessarysubstance from the peripheral surface of the wafer W, and to etch awayan unnecessary substance from the peripheral edge portion of the uppersurface of the wafer W.

In the midst of the etching process, the control section 100 drives theelectric motor M2 to lower the second link ring 44, while continuouslyrotating the spin chuck 1. That is, the ball nuts 64 of the ball threadmechanisms 62 are lowered, whereby the second link ring 44 iscorrespondingly lowered by spring forces of the compression coil springs59 and the gravity. Thus, the lift members 46 (of the link mechanisms41, 42, 43) are lowered. Therefore, the clamping members S1 to S3 arepivoted by the operation of the second movement converting mechanismFT2, whereby the wafer W is clamped by the clamping members S1 to S3with the abutment portions 96 thereof in abutment against the peripheralsurface of the wafer W (intermediate state). At this time, the clampingmembers F1 to F3 keep clamping the wafer W, so that the wafer W isclamped by all the six clamping members F1 to F3 and S1 to S3 (secondsubstrate rotation step).

In this state, the control section 100 further controls the electricmotor M1, while continuously rotating the spin chuck 1. That is, theball nuts 64 of the ball thread mechanisms 61 are lifted, whereby thefirst link ring 34 is correspondingly lifted against the spring forcesof the compressing coil springs 58. As a result, the clamping members F1to F3 are pivoted by the operation of the first movement convertingmechanism FT1, so that the abutment portions 96 thereof are retractedfrom the peripheral surface of the wafer W. Thus, the clamping membersF1 to F3 are opened in the wafer unclamping state (third substraterotation step, second clamping step). Therefore, the wafer W isthereafter clamped only by the clamping members S1 to S3, while beingcontinuously rotated.

Thus, the wafer clamping state is once switched from a first clampingstate where the wafer W is clamped by the clamping members F1 to F3 tothe intermediate state where the wafer W is clamped by all the clampingmembers F1 to F3 and S1 to S3 and then to a second clamping state wherethe wafer W is clamped by the clamping members S1 to S3 during therotation of the spin chuck 1 without stopping the rotation of the spinchuck 1 (switching step). Thus, wafer clamping positions on theperipheral surface of the wafer W can be changed during the etchingprocess performed by supplying the etching liquid to the wafer W.Therefore, the entire peripheral surface and peripheral edge portion ofthe wafer W can properly be treated without reduction in productivity.

In addition, the intermediate state where the wafer W is clamped by allthe clamping members F1 to F3 and S1 to S3 is present between the firstclamping state where the wafer W is clamped by the clamping members F1to F3 and the second clamping state where the wafer W is clamped by theclamping members S1 to S3. Therefore, the wafer is unlikely to be slideven when the wafer clamping positions are changed. Hence, the apparatusis virtually free from the generation of particles. Further, the wafer Wcan assuredly be held by the spin chuck 1 even when the wafer clampingpositions are changed. Hence, there is no possibility that the wafer Wis spun out of the spin chuck 1.

After the wafer W is treated with the etching liquid, the controlsection 100 closes the etching liquid supply valve 5 and opens thedeionized water supply valves 4, 12. Thus, a deionized water rinseprocess is performed by supplying deionized water to the upper and lowersurfaces of the wafer W. By transferring the wafer W between theclamping members F1 to F3 and the clamping members S1 to S3 in the aforesaid manner during the deionized water rinse process, the entiresurfaces of the wafer W can uniformly and properly be rinsed.

Thereafter, the control section 100 closes the deionized water supplyvalves 4, 12, and controls the motor 2 to rotate the spin chuck 1 at ahigh speed. Thus, a drying process is performed by spinning off waterfrom the upper and lower surfaces of the wafer W. In the drying process,the wafer W is preferably transferred between the clamping members F1 toF3 and the clamping members S1 to S3 in the afore said manner byswitching the wafer clamping state from the first clamping state wherethe wafer W is clamped by the clamping members F1 to F3 and unclamped bythe clamping members S1 to S3 (first substrate rotation step) throughthe intermediate state where the wafer W is clamped by all the clampingmembers F1 to F3 and S1 to S3 (second substrate rotation step) to thesecond clamping state where the wafer W is clamped by the clampingmembers S1 to S3 and unclamped by the clamping members F1 to F3 (thirdsubstrate rotation step) while continuously rotating the spin chuck 1.Thus, water droplets are prevented from remaining on the portions of thewafer W brought into abutment against the clamping members F1 to F3 andS1 to S3.

In the above explanation, the etching liquid is continuously supplied tothe wafer W in the first to third substrate rotation steps in theetching process. However, it is merely necessary to supply the etchingliquid to the wafer W at least in the first and third substrate rotationsteps for proper treatment of the entire peripheral surface andperipheral edge portion of the wafer W.

After the third substrate rotation step, the wafer W may be once clampedby all the clamping members F1 to F3 and S1 to S3 in the intermediatestate, and then subjected again to the respective processes startingfrom the first substrate rotation step.

Upon completion of the treatment of the wafer W, the abutment portions96 of the respective clamping members F1 to F3 and S1 to S3 areretracted from the peripheral surface of the wafer W, and then thetreated wafer W is unloaded from the spin chuck 1 by the substratetransport robot.

During the transfer of the wafer W between the clamping members F1 to F3and the clamping members S1 to S3, the control section 100 may controlthe motor 2 to continuously rotate the spin chuck 1 at a constantrotation speed or, as required, control the motor 2 to change therotation speed of the spin chuck 1. In either case, the wafer W is onceheld in the intermediate state for the transfer of the wafer W, so thatthe wafer W is not relatively rotated with respect to the spin chuck 1.Therefore, the generation of particles can be suppressed without slidingcontact between the wafer W and any portion of the spin chuck 1.

Where it is desired to relatively rotate the wafer W with respect to thespin chuck 1 when the wafer W is held in one of the first clampingstate, the second clamping state and the intermediate state describedabove, the control section 100 controls the motors M1, M2 to lift thelink rings 34, 44, whereby the wafer W is slightly or completelyreleased from the clamping members F1 to F3, S1 to S3 (complete/slightrelease step). In this state, the control section 100 controls the motor2 to accelerate or decelerate the rotation of the spin chuck 1(acceleration/deceleration step), whereby the wafer W is inertiallyrotated relative to the spin chuck 1. Thereafter, the wafer W is clampedagain by the clamping members F1 to F3 and/or S1 to S3 (re-clampingstep).

In the above explanation, the wafer W is first clamped by the clampingmembers F1 to F3, and then transferred to the clamping members S1 to S3.Alternatively, the wafer W may be first clamped by the clamping membersS1 to S3, and then transferred to the clamping members F1 to F3.

FIG. 10 is a diagram for explaining the construction of a substratetreatment apparatus according to a second embodiment of the presentinvention. A reference will be made again to FIGS. 1, 3, 4 and 9 for theexplanation of the second embodiment.

The substrate treatment apparatus according to the second embodiment hassubstantially the same construction as the apparatus according to thefirst embodiment, except that a spin chuck 1 thereof has a constructionas illustrated in plan in FIG. 10. In this embodiment, the threeclamping members F1 to F3 of the first clamping member set each have afirst abutment portion A and a second abutment portion B, and the threeclamping members S1 to S3 of the second clamping member set each have athird abutment portion C and a fourth abutment portion D.

FIG. 11 is a perspective view illustrating the construction of theclamping member F1. The clamping member F1 includes a generallyboat-shaped plate portion 95, and the first abutment portion A and thesecond abutment portion B thereof are provided upright as substrateclamp pins at opposite ends of the plate portion 95. A wafer supportportion 95 a is provided on a pivot center of the plate portion 95. Bypivoting the clamping member F1 about a vertical axis extending throughthe wafer support portion 95 a, the clamping member F1 can be broughtinto a state where the first abutment portion A abuts against theperipheral surface of the wafer W, a state where the second abutmentportion B abuts against the peripheral surface of the wafer W, or astate where both the first abutment portion A and the second abutmentportion B are retracted from the peripheral surface of the wafer W. Thatis, either the first abutment portion A or the second abutment portioncan selectively be brought into abutment against the peripheral surfaceof the wafer W. The clamping members F2, F3 each have the sameconstruction as the clamping member F1.

The clamping members S1 to S3 of the second clamping member set have thesame construction as the clamping members F1 to F3. That is, theclamping members S1 to S3 each have a generally boat-shaped plateportion 95, and the third abutment portion C and the fourth abutmentportion D are provided upright as substrate clamp pins at opposite endsof the plate portion 95. A wafer support portion 95 a is provided on apivot center of the plate portion 95. By pivoting the clamping member S1to S3 about a vertical axis extending through the wafer support portion95 a, the clamping member S1 to S3 can be brought into a state where thethird abutment portion C abuts against the peripheral surface of thewafer W, a state where the fourth abutment portion D abuts against theperipheral surface of the wafer W, or a state where both the thirdabutment portion C and the fourth abutment portion D are retracted fromthe peripheral surface of the wafer W. That is, either the thirdabutment portion C or the fourth abutment portion D can selectively bebrought into abutment against the peripheral surface of the wafer W.

With the same arrangement as employed in the first embodiment describedabove, the clamping members F1 to F3 are operative in association witheach other and, similarly, the clamping members S1 to S3 are operativein association with each other.

In the second embodiment, the wafer clamping state can selectively beswitched among a state where the wafer W is clamped by the three firstabutment portions A, a state where the wafer W is clamped by the threefirst abutment portions A and the three third abutment portions C, astate where the wafer W is clamped by the three first abutment portionsA and the three fourth abutment portions D, a state where the wafer W isclamped by the three second abutment portions B, a state where the waferW is clamped by the three second abutment portions B and the three thirdabutment portions C, a state where the wafer W is clamped by the threesecond abutment portions B and the three fourth abutment portions D, astate where the wafer W is clamped by the three third abutment portionsC, a state where the wafer W is clamped by the three fourth abutmentportions D, and a state where the first to fourth abutment portions A toD are all retracted from the peripheral surface of the wafer W.

FIG. 12( a) is a partial sectional view illustrating an arrangement fortransmitting the driving force between the first rotative movable member81 and the lift member 46 for the clamping member F1 to F3, and FIG. 12(b) is a partial sectional view illustrating an arrangement fortransmitting the driving force between the second rotative movablemember 82 and the lift member 46 for the clamping member S1 to S3.

A bracket 81B having a generally inverted L-shape in section is fixed tothe first rotative movable member 81. The lift member 46 is insertedthrough an insertion hole 110 formed in the bracket 81B. A springstopper pin 111 extends through a portion of the lift member 46 betweenthe bracket 81B and the lower plate 23 of the spin base 21. A firstcompression coil spring 58A is wound around the lift member 46 betweenthe bracket 81B and the spring stopper pin 111, and a second compressioncoil spring 58B is wound around the lift member 46 between the bracket81B and the first link ring 34.

With this arrangement, when the first rotative movable member 81 islifted, the upward driving forces are transmitted to the lift members 46through the first compression coil springs 58A to lift the lift members46. Thus, the clamping members F1 to F3 are pivoted by the operation ofthe first movement converting mechanism FT1 to move the first abutmentportions A toward the peripheral surface of the wafer W. With the firstabutment portions A in abutment against the peripheral surface of thewafer W, the first rotative movable member 81 is lifted against thespring forces of the first compression coil springs 58A, whereby thewafer W is clamped by the first abutment portions A of the threeclamping members F1 to F3 and resiliently held by the spring forces ofthe first compression coil springs 58A.

Similarly, when the first rotative movable member 81 is lowered, thedownward driving forces are transmitted to the first link ring 34 andthe lift members 46 through the second compression coil springs 58B tolower the lift members 46. Thus, the clamping members F1 to F3 arepivoted by the operation of the first movement converting mechanism FT1to move the second abutment portions B toward the peripheral surface ofthe wafer W. With the second abutment portions B in abutment against theperipheral surface of the wafer W, the first rotative movable member 81is lowered against the spring forces of the second compression coilsprings 58B, whereby the wafer W is clamped by the second abutmentportions B of the three clamping members F1 to F3 and resiliently heldby the spring forces of the second compression coil springs 58B.

The transmission of the driving forces between the second rotativemovable member 82 and the lift members 46 for the clamping members S1 toS3 is achieved by the same arrangement as described above. That is, abracket 82B having a generally inverted L-shape in section is fixed tothe second rotative movable member 82. The lift member 46 is insertedthrough an insertion hole 120 formed in the bracket 82B. A springstopper pin 121 extends through a portion of the lift member 46 betweenthe bracket 82B and the lower plate 23 of the spin base. A firstcompression coil spring 59A is wound around the lift member 46 betweenthe bracket 82B and the spring stopper pin 121, and a second compressioncoil spring 59B is wound around the lift member 46 between the bracket82B and the second link ring 44.

With this arrangement, when the second rotative movable member 82 islifted, the wafer W is resiliently held with the third abutment portionsC of the clamping members S1 to S3 in abutment against the peripheralsurface of the wafer W. When the second rotative movable member 82 islowered, the wafer W is resiliently held with the fourth abutmentportions D of the clamping members S1 to S3 in abutment against theperipheral surface of the wafer W.

Next, an explanation will be given to the flow of the treatment of thewafer W.

When a wafer W is loaded onto the spin chuck 1 by the substratetransport robot not shown, the motor 2 and the rotative drive mechanism9 are kept in halt under the control of the control section 100.Further, the control section 100 controls the lift drive mechanism 7 tomove the shield plate 6 to the retracted position above the spin chuck1, and the valves 10, 12, 4, 5 are kept closed under the control of thecontrol section 100.

The control section 100 controls the first and second motors M1, M2 tolocate the first and second rotative movable members 81, 82 at anintermediate height. The intermediate height is corresponds to a statewhere the clamping members F1 to F3 are opened with the first and secondabutment portions A, B thereof retracted radially outwardly of the spinbase 21 out of abutment against the peripheral surface of the wafer W,and the clamping members S1 to S3 are opened with the third and fourthabutment portions C, D thereof retracted radially outwardly of the spinbase 21 out of abutment against the peripheral surface of the wafer W(see FIG. 13( a)). In this state, the substrate transport robot placesthe wafer W on the wafer support portions 95 a of the plate portions 95of the clamping members F1 to F3 and S1 to S3.

In this state, the control section 100 controls, for example, the firstmotor M1 to drive the first ball thread mechanisms 61 so as to lift theball nuts 64. Thus, the first rotative movable member 81 is lifted, sothat the lift members 46 are moved up by the upward driving forcesreceived from the compression coil springs 58A. As a result, theclamping members F1 to F3 are pivoted, whereby the first abutmentportions A thereof are brought into abutment against the peripheralsurface of the wafer W. Thus, the wafer W is clamped by the firstabutment portions A of the clamping members F1 to F3 as schematicallyillustrated in FIG. 13( b). At this time, the clamping members S1 to S3are kept open (with the third and fourth abutment portions C, D thereofretracted from the peripheral surface of the wafer W), because theelectric motor M2 is not driven.

Thereafter, the control section 100 energizes the motor 2 to rotate thespin chuck 1 (first substrate rotation step). At the same time, the liftdrive mechanism 7 is controlled to lower the shield plate 6 to thevicinity of the wafer W, and then the rotative drive mechanism 9 isenergized to rotate the shield plate 6 in synchronization with the spinchuck 1.

Subsequently, the control section 100 opens the etching liquid supplyvalve 5 and the nitrogen gas supply valve 10. Thus, the etching liquidis supplied toward the center of the lower surface of the wafer W fromthe center nozzle 26 (treatment liquid supply step, etching liquidsupply step). The etching liquid flows radially outwardly over the lowersurface of the wafer W and further flows over the peripheral surface ofthe wafer W onto the upper surface of the wafer W. The amount of theetching liquid flowing onto the upper surface of the wafer W iscontrolled by ejecting nitrogen gas from the center of the shield plate6. As a result, the etching process is performed to etch the entire rearsurface of the wafer W, to etch away an unnecessary substance from theperipheral surface of the wafer W, and to etch away an unnecessarysubstance from the peripheral edge portion of the upper surface of thewafer W.

In the midst of the etching process, the control section 100 drives theelectric motor M2 to lift the second rotative movable member 82, whilecontinuously rotating the spin chuck 1. That is, the ball nuts 64 of theball thread mechanisms 62 are lifted, so that the lift members 46 of thelink mechanisms 41, 42, 43 are correspondingly lifted by upward forcesreceived from the first compression coil springs 59A. Therefore, theclamping members S1 to S3 are pivoted by the operation of the secondmovement converting mechanism FT2. Thus, the wafer W is clamped by theclamping members S1 to S3 with the third abutment portions C thereof inabutment against the peripheral surface of the wafer W (intermediatestate). At this time, the first abutment portions A of the clampingmembers F1 to F3 keep clamping the wafer W, so that the wafer W isclamped by the six abutment portions A, C of the clamping members F1 toF3 and S1 to S3 as shown in FIG. 13( c) (second substrate rotationstep).

In this state, the control section 100 further controls the electricmotor M1, while continuously rotating the spin chuck 1. That is, theball nuts 64 of the ball thread mechanisms 61 are lowered to lower thefirst rotative movable member 81 to the intermediate height. As aresult, the lift members 46 are lowered, and the clamping members F1 toF3 are pivoted by the operation of the first movement convertingmechanism FT1, whereby the first abutment portions A of the clampingmembers F1 to F3 are retracted from the peripheral surface of the waferW. Thus, the clamping members F1 to F3 are opened in the waferunclamping state (third substrate rotation step). Therefore, the wafer Wis thereafter clamped by the three third abutment portions C of theclamping members S1 to S3 as shown in FIG. 13( d), while beingcontinuously rotated.

In this state, the control section 100 further controls the electricmotor M1, while continuously rotating the spin chuck 1. That is, theball nuts 64 of the ball thread mechanisms 61 are lowered, so that thefirst rotative movable member 81 is further lowered from theintermediate height. As a result, the lift members 46 are lowered, andthe clamping members F1 to F3 are pivoted by the operation of the firstmovement converting mechanism FT1, whereby the second abutment portionsB of the clamping members F1 to F3 are brought into abutment against theperipheral surface of the wafer W. Thus, the wafer W is clamped by thethree second abutment portions B of the clamping members F1 to F3 andthe three third abutment portions C of the clamping members S1 to S3 asshown in FIG. 13( e), while being continuously rotated (fourth substraterotation step).

In this state, the control section 100 drives the electric motor M2 tolower the second rotative movable member 82 to the intermediate height,while continuously rotating the spin chuck 1. That is, the ball nuts 64of the ball thread mechanisms 62 are lowered, so that the lift members46 of the link mechanisms 41, 42, 43 are correspondingly lowered.Therefore, the clamping members S1 to S3 are pivoted by the operation ofthe second movement converting mechanism FT2, whereby the third abutmentportions C of the clamping members S1 to S3 are retracted from theperipheral surface of the wafer W. Thus, the wafer W is clamped by thethree second abutment portions B of the clamping members F1 to F3 asshown in FIG. 13( f) (fifth substrate rotation step). In this manner,the wafer W is transferred from the first abutment portions A to thesecond abutment portions B of the clamping members F1 to F3 (abutmentportion switching step).

Thereafter, the control section 100 further drives the electric motor M2to further lower the second rotative movable member 82 from theintermediate height, while continuously rotating the spin chuck 1. Thelift members 46 are correspondingly lowered, and the clamping members S1to S3 are pivoted by the operation of the second movement convertingmechanism FT2, whereby the fourth abutment portions D of the clampingmembers S1 to S3 are brought into abutment against the peripheralsurface of the wafer W. Thus, the wafer W is clamped by the three secondabutment portions B of the clamping members F1 to F3 and the threefourth abutment portions D of the clamping members S1 to S3 as shown inFIG. 13( g) (sixth substrate rotation step).

In this state, the control section 100 controls the electric motor M1,while continuously rotating the spin chuck 1. That is, the ball nuts 64of the ball thread mechanisms 61 are lifted to lift the first rotativemovable member 81 to the intermediate height. As a result, the liftmembers 46 are lifted, and the clamping members F1 to F3 are pivoted bythe operation of the first movement converting mechanism FT1, wherebythe second abutment portions B of the clamping members F1 to F3 areretracted from the peripheral surface of the wafer W. Thus, the wafer Wis clamped by the three fourth abutment portions D of the clampingmembers S1 to S3 as shown in FIG. 13( h), while being continuouslyrotated (seventh substrate rotation step). Thus, the wafer W istransferred from the third abutment portions C to the fourth abutmentportions D of the clamping members S1 to S3 (abutment portion switchingstep).

Where the entire peripheral surface of the wafer W is to be treated fora predetermined period T (e.g., 60 seconds), the first, third, fifth andseventh substrate rotation steps are each performed for a period T/3(e.g., 20 seconds). Thus, the etching liquid can be supplied to theportions of the peripheral surface of the wafer W clamped switchably bythe first to fourth abutment portions A to D for the predeterminedperiod T. Therefore, the time required for the etching process per waferW is the total of the predetermined period T and the time required forthe second, fourth and sixth substrate rotation steps. Accordingly, theprocess time can be minimized by reducing the time required for thesecond, fourth and sixth substrate rotation steps as much as possible.

In the aforesaid first embodiment, on the other hand, the first andthird substrate rotation steps should each be performed for thepredetermined period T in order to supply the etching liquid to theportions of the wafer W clamped switchably by the abutment portions 96of the clamping members F1 to F3 and S1 to S3 for the predeterminedperiod T. That is, the time required for the etching process is thetotal of twice the predetermined period (e.g., 120 seconds) and the timerequired for the second substrate rotation step.

Thus, the time required for the etching process can drastically bereduced according to the second embodiment.

As described above, the substrate clamping state is switched from afirst clamping state where the wafer W is clamped by the first abutmentportions A through a first intermediate state where the wafer W isclamped by the first abutment portions A and the third abutment portionsC to a second clamping state where the wafer W is clamped by the thirdabutment portions C, then switched from the second clamping statethrough a second intermediate state where the wafer W is clamped by thethird abutment portions C and the second abutment portions B to a thirdclamping state where the wafer W is clamped by the second abutmentportion B, and switched from the third clamping state through a thirdintermediate state where the wafer W is clamped by the second abutmentportions B and the fourth abutment portions D to a fourth clamping statewhere the wafer W is clamped by the fourth abutment portions D duringthe rotation of the spin chuck 1 without stopping the rotation of thespin chuck 1. Thus, the wafer clamping positions on the peripheralsurface of the wafer W can be changed during the supply of the etchingliquid to the wafer W. Therefore, the entire peripheral surface andperipheral edge portion of the wafer W can properly be treated withoutreduction in productivity.

In addition, the wafer clamping state is once switched from a statewhere the wafer W is clamped by the clamping members F1 to F3 to anintermediate state where the wafer W is clamped by the clamping membersF1 to F3 and S1 to S3, and then switched to a state where the wafer W isclamped by the clamping members S1 to S3 as in the aforesaid firstembodiment. Therefore, the wafer W is unlikely to be slid even when thewafer clamping positions are changed. Further, the wafer W can assuredlybe held even when the wafer clamping positions are changed.

After the wafer W is treated with the etching liquid, the controlsection 100 closes the etching liquid supply valve 5 and opens thedeionized water supply valves 4, 12. Thus, the deionized water rinseprocess is performed by supplying deionized water to the upper and lowersurfaces of the wafer W. By transferring the wafer W among the first tofourth abutment portions A to D in the aforesaid manner during thedeionized water rinse process, the entire surfaces of the wafer W canuniformly and properly be rinsed, and the time required for the rinseprocess can be reduced.

Thereafter, the control section 100 closes the deionized water supplyvalves 4, 12, and controls the motor 2 to rotate the spin chuck 1 at ahigh speed. Thus, the drying process is performed by spinning off waterfrom the upper and lower surfaces of the wafer W. In the drying process,the wafer W is preferably transferred among the first to fourth abutmentportions A to D by performing the aforesaid first to seventh substraterotation steps while continuously rotating the spin chuck 1. Thus, waterdroplets are prevented from remaining on the portions of the wafer Wbrought into abutment against the clamping members F1 to F3 and S1 toS3.

In the above explanation, the etching liquid is continuously supplied tothe wafer W in the first to seventh substrate rotation steps in theetching process. However, it is merely necessary to supply the etchingliquid to the wafer W at least in the first, third and seventh substraterotation steps for proper treatment of the entire peripheral surface andperipheral edge portion of the wafer W.

After the seventh substrate rotation step, the wafer W may be onceclamped in an intermediate state by the fourth abutment portions D andthe first abutment portions A (eighth substrate rotation step, see FIG.13( i)) and then subjected again to the respective processes startingfrom the first substrate rotation step (see FIG. 13( b)).

Upon completion of the treatment of the wafer W, the first to fourthabutment portions A, B, C, D of the clamping members F1 to F3 and S1 toS3 are retracted from the peripheral surface of the wafer W (see FIG.13( a)), and then the treated wafer W is unloaded from the spin chuck 1by the substrate transport robot.

FIG. 14 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a third embodiment of thepresent invention. In FIG. 14, components corresponding to those shownin FIG. 4 are denoted by the same reference characters as in FIG. 4.

In the embodiments described above, the first bearing 71 transmits thedriving force between the first non-rotative movable member 68 and thefirst rotative movable member 81, while permitting the relative rotationof the first rotative movable member 81 with respect to the firstnon-rotative movable member 68 about the rotary shaft 25. The secondbearing 72 transmits the driving force between the second non-rotativemovable member 78 and the second rotative movable member 82, whilepermitting the relative rotation of the second rotative movable member82 with respect to the second non-rotative movable member 78 about therotary shaft 25.

In this embodiment, on the other hand, a plurality of rolls 201 (atleast two rolls 201) are provided on an upper surface of the firstnon-rotative movable member 68, and a plurality of rolls 202 (at leasttwo rolls 202) are provided on an upper surface of the secondnon-rotative movable member 78. The rolls 201 and the rolls 202 rollalong circular tracks about the rotary shaft 25 in contact with arolling surface 204 formed on a lower surface of the first ring-shapedrotative movable member 81 and a rolling surface 205 formed on a lowersurface of the second ring-shaped rotative movable member 82,respectively. This arrangement allows for the relative rotation of thefirst rotative movable member 81 with respect to the first non-rotativemovable member 68 about the rotary shaft 25 and the transmission of thedriving force from the first non-rotative movable member 68 to the firstrotative movable member 81. Further, this arrangement allows for therelative rotation of the second rotative movable member 82 with respectto the second non-rotative movable member 78 about the rotary shaft 25and the transmission of the driving force from the second non-rotativemovable member 78 to the second rotative movable member 82.

When the lift members 46 of the link mechanisms 31, 32, 33 of the firstmovement converting mechanism FT1 are lowered to the lowermost height,the first non-rotative movable member 68 is lowered to a position atwhich the rolls 201 do not contact the rolling surface 204. Similarly,when the lift members 46 of the link mechanisms 41, 42, 43 of the secondmovement converting mechanism FT2 are lowered to the lowermost height,the second non-rotative movable member 78 is lowered to a position atwhich the rolls 202 do not contact the rolling surface 205. The secondrotative movable member 82 providing the rolling surface 205 isconnected to lower ends of the lift members 46 and the guide shafts 49.

The rolls 201 and the rolls 202 are provided on the upper surfaces ofthe first non-rotative movable member 68 and the second non-rotativemovable member 78, respectively. For example, four rolls 201 may bedisposed at positions RP1 (see FIG. 6) on the upper surface of the firstnon-rotative movable member 68, and four rolls 202 may be disposed atpositions RP2 (see FIG. 6) on the upper surface of the secondnon-rotative movable member 78. In FIG. 6, the roll positions PR1 arelocated in pairs on opposite sides of the two first ball threadmechanisms 61, 61 which are provided in opposed relation with the rotaryshaft 25 interposed therebetween. Similarly, the roll positions PR2 arelocated in pairs on opposite sides of the two second ball threadmechanisms 62, 62 which are provided in opposed relation with the rotaryshaft 25 interposed therebetween.

Of course, the arrangements of the rolls 201 and the rolls 202 may bemodified. For example, three rolls may be disposed on the upper surfaceof each of the first non-rotative movable member 68 and the secondnon-rotative movable member 78. Alternatively, five rolls may bedisposed on the upper surface of each of the first non-rotative movablemember 68 and the second non-rotative movable member 78.

Further, the first non-rotative movable member 68 and the secondnon-rotative movable member 78 are not necessarily required to have aring shape, but may have any of various configurations as long as therolls 201 and the rolls 202 can be moved up and down in association withthe movements of the first ball thread mechanisms 61 and the second ballthread mechanisms 62.

For example, a pair of movable members provided in the vicinity of thepair of first ball thread mechanisms 61, 61 may be employed instead ofthe first non-rotative movable member 68. In this case, rolls 201, 201are respectively provided on the movable members, and the movablemembers are respectively moved up and down by the first ball threadmechanisms 61, 61. The pair of first ball thread mechanisms 61, 61 areinterlocked by the ring-shaped first gear 54, so that the pair ofmovable members are movable up and down in association with each other.Of course, the second non-rotative movable member 78 may also bemodified in this manner.

FIG. 15 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a fourth embodiment of thepresent invention. In FIG. 15, components corresponding to those shownin FIG. 14 are denoted by the same reference characters as in FIG. 14.

In this embodiment, a plurality of rolls 211 (at least two rolls 211)are provided on the lower surface of the first rotative movable member81, and a plurality of rolls 212 (at least two rolls 212) are providedon the lower surface of the second rotative movable member 82. The rolls211 and the rolls 212 roll along circular tracks about the rotary shaft25 in contact with a rolling surface 214 formed on the upper surface ofthe first ring-shaped non-rotative movable member 68 and a rollingsurface 215 formed on the upper surface of the second ring-shapednon-rotative movable member 78, respectively. This arrangement allowsfor the relative rotation of the first rotative movable member 81 withrespect to the first non-rotative movable member 68 about the rotaryshaft 25 and the transmission of the driving force from the firstnon-rotative movable member 68 to the first rotative movable member 81.Further, this arrangement allows for the relative rotation of the secondrotative movable member 82 with respect to the second non-rotativemovable member 78 about the rotary shaft 25 and the transmission of thedriving force from the second non-rotative movable member 78 to thesecond rotative movable member 82.

When the lift members 46 of the link mechanisms 31, 32, 33 of the firstmovement converting mechanism FT1 are lowered to the lowermost height,the first non-rotative movable member 68 is lowered to a position atwhich the rolls 211 do not contact the rolling surface 214. Similarly,when the lift members 46 of the link mechanisms 41, 42, 43 of the secondmovement converting mechanism FT2 are lowered to the lowermost height,the second non-rotative movable member 78 is lowered to a position atwhich the rolls 212 do not contact the rolling surface 215. The secondrotative movable member 82 to which the rolls 212 are fixed is connectedto lower ends of the lift members 46 and the guide shafts 49.

The rolls 211 and the rolls 212 are provided on the lower surfaces ofthe first rotative movable member 81 and the second rotative movablemember 82, respectively. For example, the rolls 211 may be disposed onthe lower surface of the first rotative movable member 81 below theguide shafts 47 (see FIG. 3), and the rolls 212 may be disposed on thelower surface of the second rotative movable member 82 below the guideshafts 49 (see FIG. 3). That is, three rolls are provided as the rolls211 or 212, which are arranged equiangularly around the rotary shaft 25in this embodiment.

Of course, the arrangements of the rolls 211 and the rolls 212 may bemodified. For example, two or four or more rolls may be disposed on thelower surface of each of the first rotative movable member 81 and thesecond rotative movable member 82.

Further, the first rotative movable member 81 and the second rotativemovable member 82 are not necessarily required to have a ring shape, butmay have any of various configurations as long as the rolls 211 and therolls 212 can roll along the rolling surfaces 214 and 215 formed on theupper surfaces of the first non-rotative movable member 68 and thesecond non-rotative movable member 78, respectively.

For example, a rotative movable member fixed to the lower ends of thelift members 46 of the link mechanisms 31, 32, 33 of the first movementconverting mechanism FT1 may be employed instead of the first rotativemovable member 81, and rolls 211 may be fixed to the rotative movablemember. The second rotative movable member 81 may also be modified inthis manner.

In this case, however, bushes 216, 217 are preferably provided on thelower plate 23 of the spin base 21 as vertical guide means forvertically guiding the lift members 46, as shown in FIG. 16. In thiscase, the guide shafts 47, 49 and the bushes 48 as vertical guide meansfor the guide shafts 47, 49 are not required.

FIG. 17 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a fifth embodiment of thepresent invention. In FIG. 17, components corresponding to those shownin FIGS. 14 and 15 are denoted by the same reference characters as inFIGS. 14 and 15.

In this embodiment, rolls 201 are provided on the upper surface of thefirst non-rotative movable member 68. The rolls 201 roll along a rollingsurface 204 formed on the lower surface of the first rotative movablemember 81. Further, rolls 212 are provided on the lower surface of thesecond rotative movable member 82. The rolls 212 roll along a rollingsurface 215 formed on the upper surface of the second non-rotativemovable member 78. That is, this embodiment employs the arrangement ofthe third embodiment and the arrangement of the fourth embodiment incombination.

Therefore, the arrangement associated with the first non-rotativemovable member 68 may be modified in the same manner as described in thethird embodiment, and the arrangement associated with the secondrotative movable member 82 may be modified in the same manner asdescribed in the fourth embodiment.

Of course, rolls 202 may be provided on the upper surface of the secondnon-rotative movable member 78, so that the rolls 202 can roll along arolling surface 205 formed on the lower surface of the second rotativemovable member 82 (see FIG. 14). Further, rolls 211 may be provided onthe lower surface of the first rotative movable member 81, so that therolls 211 can roll along a rolling surface 214 formed on the uppersurface of the first non-rotative movable member 68 (see FIG. 15).

In this case, the arrangement associated with the second non-rotativemovable member 78 may be modified in the same manner as described in thethird embodiment, and the arrangement associated with the first rotativemovable member 81 may be modified in the same manner as described in thefourth embodiment.

Although the rolls are employed as rolling members in the third, fourthand fifth embodiments, spherical members (balls) may be employed insteadof the rolls. Alternatively, toothed rolls (gears) may be employed. Inthis case, circular gear portions (racks) to be meshed with the toothedrolls may respectively be provided along the tracks of the toothed rollson the rolling surfaces 204, 205, 214, 215.

FIG. 18 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a sixth embodiment of thepresent invention. In FIG. 18, components corresponding to those shownin FIG. 14 are denoted by the same reference characters as in FIG. 14.

In this embodiment, permanent magnets 221 and 222 are respectively fixedonto the upper surfaces of the first non-rotative movable member 68 andthe second non-rotative movable member 78. Permanent magnets 224 and 225are respectively fixed onto the lower surfaces of the first rotativemovable member 81 and the second rotative movable member 82. Thepermanent magnets 221 and 224 are disposed in vertically opposedrelation with their opposed poles having the same polarity (N-pole orS-pole). When the permanent magnet 221 is sufficiently close to thepermanent magnet 224, the permanent magnet 224 is magnetically levitatedabove the permanent magnet 221 by a repulsive force occurringtherebetween. Similarly, the permanent magnets 222 and 225 are disposedin vertically opposed relation with their opposed poles having the samepolarity (N-pole or S-pole). When the permanent magnet 222 issufficiently close to the permanent magnet 225, the permanent magnet 225is magnetically levitated above the permanent magnet 222 by a repulsiveforce occurring therebetween.

This arrangement permits the relative rotation of the first rotativemovable member 81 with respect to the first non-rotative movable member68 about the rotary shaft 25, and allows for the transmission of thedriving force from the first non-rotative movable member 68 to the firstrotative movable member 81 when the first non-rotative movable member 68is lifted. Further, this arrangement permits the relative rotation ofthe second rotative movable member 82 with respect to the secondnon-rotative movable member 78 about the rotary shaft 25, and allows forthe transmission of the driving force from the second non-rotativemovable member 78 to the second rotative movable member 82 when thesecond non-rotative movable member 78 is lifted.

The permanent magnets 221, 222, 224, 225 may each have a ring shape assurrounding the rotary shaft 25. Where one of the permanent magnets 221,224 provided in pair in opposed relation has a ring shape, the otherpermanent magnet is not necessarily required to have a ring shape, butmay include a plurality of permanent magnet pieces (e.g., three or morepermanent magnet pieces) preferably equiangularly disposed in opposedrelation to the ring-shaped permanent magnet with the opposed poles ofthe ring-shaped permanent magnet and the permanent magnet pieces havingthe same polarity. The other pair of permanent magnets 222, 225 disposedin opposed relation may also be modified in this manner.

Further, electromagnetic devices may be employed instead of thepermanent magnets. Where the electromagnetic devices are employed,however, electric wiring is required. Therefore, it is preferred thatthe electromagnetic devices are provided on the first non-rotativemovable member 68 and/or the second non-rotative movable member 78, andthe permanent magnets are provided on the first rotative movable member81 and the second rotative movable member 82.

FIG. 19 is a sectional view for explaining the construction of asubstrate treatment apparatus according to a seventh embodiment of thepresent invention. In FIG. 19, components corresponding to those shownin FIG. 14 are denoted by the same reference characters as in FIG. 14.

In this embodiment, the first non-rotative movable member 68 and thesecond non-rotative movable member 78 respectively have gas ejectingportions 231 and 232 for ejecting a gas upward. The pressures of the gasejected from the gas ejecting portions 231 and 232 are respectivelyreceived by a pressure receiving surface 234 formed on the lower surfaceof the first rotative movable member 81 and a pressure receiving surface235 formed on the lower surface of the second rotative movable member82. The pressure receiving surfaces 234, 235 of the first rotativemovable member 81 and the second rotative movable member 82 each have aring shape centered on the rotary shaft 25 and are each contained in aplane perpendicular to the rotary shaft 25.

With this arrangement, when the first non-rotative movable member 68 islifted to bring the gas ejecting portion 231 thereof sufficiently closeto the pressure receiving surface 234, the first rotative movable member81 can be levitated by the pressure of the ejected gas. Similarly, whenthe second non-rotative movable member 78 is lifted to bring the gasejecting portion 232 thereof sufficiently close to the pressurereceiving surface 235, the second rotative movable member 82 can belevitated by the pressure of the ejected gas.

That is, the transmission of the driving force from the firstnon-rotative movable member 68 to the first rotative movable member 81can be achieved, while the relative rotation of the first rotativemovable member 81 with respect to the first non-rotative movable member68 about the rotary shaft 25 is permitted. Further, the transmission ofthe driving force from the second non-rotative movable member 78 to thesecond rotative movable member 82 can be achieved, while the relativerotation of the second rotative movable member 82 with respect to thesecond non-rotative movable member 78 about the rotary shaft 25 ispermitted.

As illustrated on a greater scale in FIG. 20, the gas ejecting portions231, 232 each include a ring-shaped duct 236, 237 centered on the rotaryshaft 25 and having a rectangular cross-section, and a plurality of gasejection ports (holes or slits) 238, 239 provided in an upper face ofthe duct 236, 237. The gas (air or an inert gas such as nitrogen gas) issupplied to the ducts 236, 237 from a pressurized gas supply source 245through gas supply passages 241, 242 under pressure.

The ducts 236, 237 are not necessarily required to have a ring shape,but may each be partitioned in a plurality of duct portions arranged inspaced relation circumferentially along the ring-shaped pressurereceiving surface 234, 235.

Alternatively, ring-shaped pressure receiving surfaces may respectivelybe provided on the upper surfaces of the first non-rotative movablemember 68 and the second non-rotative movable member 78, and the firstrotative movable member 81 and the second rotative movable member 82 mayrespectively be provided with gas ejecting portions for ejecting the gasdownward toward the pressure receiving surfaces. Further, ring-shapedpressure receiving surfaces may respectively be provided on the uppersurface of the first non-rotative movable member 68 and on the lowersurface of the second rotative movable member 82, and the first rotativemovable member 81 and the second non-rotative movable member 78 mayrespectively be provided with a gas ejecting portion for ejecting thegas downward and a gas ejecting portion for ejecting the gas upward.Similarly, ring-shaped pressure receiving surfaces may respectively beprovided on the lower surface of the first rotative movable member 81and on the upper surface of the second non-rotative movable member 78,and the first non-rotative movable member 68 and the second rotativemovable member 82 may respectively be provided with a gas ejectingportion for ejecting the gas upward and a gas ejecting portion forejecting the gas downward. In these cases, however, the compressed gasshould be supplied to the rotary components, so that the gas supplypassages may each have a complicated structure.

As described above, the bearing mechanisms shown in FIG. 4, the rollingmechanisms shown in FIG. 14 and the like, the magnetic levitationmechanisms shown in FIG. 18 or the pneumatic levitation mechanisms shownin FIG. 19 can be employed as the driving force transmission mechanismsfor transmitting the driving forces from the non-rotative movablemembers 68, 78 to the rotative movable members 81, 82. For thetransmission of the driving force from the first non-rotative movablemember 68 to the first rotative movable member 81 and for thetransmission of the driving force from the second non-rotative movablemember 78 to the second rotative movable member 82, the same type ofdriving force transmission mechanisms are not necessarily required, butdifferent types of driving force transmission mechanisms may be employedin combination.

FIG. 21 is a diagram for explaining the construction of a substratetreatment apparatus according to an eighth embodiment of the presentinvention, and illustrates the internal construction of a spin chuck inplan. In FIG. 21, components corresponding to those shown in FIG. 3 aredenoted by the same reference characters as in FIG. 3. For explanationof this embodiment, a reference is made again to FIGS. 3, 4 and 9.

In this embodiment, the clamping members S1 to S3 (see FIG. 3) employedin the first embodiment are not provided, but only the three clampingmembers F1 to F3 are provided for clamping a wafer W. Further, thesecond movement converting mechanism FT2 (see FIG. 3) is not provided,but only the first movement converting mechanism FT1 is provided foroperating the clamping members F1 to F3 in association with each other.This embodiment correspondingly differs from the first embodiment, andthe second motor M2 and the driving force transmission mechanism fortransmitting the driving force from the second motor M2 to the secondmovement converting mechanism FT2 (the second ball thread mechanism 62,the bearing 53, the second gear 55, the second bearing 72, the secondnon-rotative movable member 78, the second rotative movable member 82and the like shown in FIG. 4) are obviated.

In this embodiment, the spin chuck 1 is rotated with the wafer W clampedby the clamping members F1 to F3 (rotation step). During this period,the control section 100 controls the motor M1 to lift the link ring 34,whereby the wafer W is slightly or completely released from the clampingmembers F1 to F3 (complete/slight release step) In this state, thecontrol section 100 accelerates or decelerates the rotation of the motorM (acceleration/deceleration step), whereby the wafer W is inertiallyrotated relative to the spin base 21. Therefore, the clamping members F1to F3 are moved relative to the wafer W. When the link member 34 islowered again for clamping the wafer W by the clamping members F1 to F3(re-clamping step), the wafer clamping positions are changed during therotation of the wafer W.

With this arrangement, the wafer clamping positions can be changedwithout stopping the rotation of the spin chuck 1. Therefore, the entireperipheral edge portion of the wafer W can uniformly be treated withoutreduction in productivity.

FIG. 22 is a diagram for explaining a ninth embodiment of the presentinvention and, particularly, a perspective view illustrating the commonconstruction of clamping members 300 employed instead of the clampingmembers F1 to F3 shown in FIG. 21. The clamping members 300 each includea base plate portion 320, a support portion 321 provided on the baseportion 320 for supporting a peripheral edge portion of a lower surfaceof a wafer W, and first and second abutment portions 331, 332 forclamping the wafer W in abutment against a peripheral surface of thewafer W. The base portion 320 is connected to the shaft 35. The supportportion 321 is located above the rotation axis 35 a of the shaft 35.

By rotating the clamping member 300 about the rotation axis 35 a, thefirst and second abutment portions 331, 332 are moved toward and awayfrom the peripheral surface of the wafer W. Thus, the clamping member300 can selectively assume a first clamping position where the firstabutment portion 331 clamps the wafer W in abutment against theperipheral surface of the wafer W, a second clamping position where thesecond abutment portion 332 clamps the wafer W in abutment against theperipheral surface of the wafer W, and a retracted position where bothof the first and second abutment portions 331, 332 are retracted fromthe peripheral surface of the wafer W. When an untreated wafer W isloaded into the substrate treatment apparatus and held on the spin chuck1, or when a treated wafer W is unloaded from the spin chuck 1, theclamping members 300 each assume the retracted position.

With this arrangement, the control section 100 controls the motor M1 tooperate the clamping members 300 so as to selectively bring the firstand second abutment portions 331, 332 into abutment against the wafer Wduring the rotation of the spin chuck 1. As a result, the wafer clampingpositions can be changed during the rotation of the spin chuck 1 withoutstopping the rotation. If the control section 100 controls the motor 2to continuously rotate the spin chuck 1 at a constant speed at thistime, the wafer W is not relatively rotated with respect to the spinchuck 1. Therefore, the generation of particles can be suppressedwithout sliding contact between the lower surface of the wafer W and thesupport portions 321.

If it is desired to change the lower surface portions of the wafer W incontact with the support portions 321, the control section 100 controlsthe motor 2 to accelerate or decelerate the rotation of the spin chuck 1so as to relatively rotate the wafer W with respect to the spin chuck 1during the switching between the first and second abutment portions 331and 332.

In the arrangements illustrated in FIGS. 21 and 22, any of the bearingmechanisms, the rolling mechanisms, the magnetic levitation mechanismsand the pneumatic levitation mechanisms described above may be employedfor driving the clamping members F1 to F3, 300.

In the embodiments described above, the first rotative movable member 81and the second rotative movable member 82 each have a ring shape, butare not necessarily required to have the ring shape. Similarly, thefirst and second non-rotative movable members 68, 78 are not necessarilyrequired to have the ring shape.

In the first to third embodiments described above, the link mechanisms31 to 33, 41 to 43 are operated in association with each other by thelink ring 34, 44. However, the lift members 46 of the link mechanisms 31to 33 can be moved up and down in association with each other and thelift members 46 of the link mechanisms 41 to 43 can be moved up and downin association with each other without the provision of the annular linkrings 34, 44, as long as the first rotative movable member 81 and thesecond rotative movable member 82 each have the ring shape.

In the first to seventh embodiments, the wafer W is first clamped by theclamping members F1 to F3, and then transferred to the clamping membersS1 to S3. Alternatively, the wafer W may first be clamped by theclamping members S1 to S3, and then transferred to the clamping membersF1 to F3.

During the transfer of the wafer W between the clamping members F1 to F3and the clamping members S1 to S3, the control section 100 may controlthe motor 2 to continuously rotate the spin chuck 1 at a constantrotation speed and, as required, may control the motor 2 to change therotation speed of the spin chuck 1. In either case, the wafer W is onceclamped in the intermediate state for the transfer of the wafer W, sothat the wafer W is not relatively rotated with respect to the spinchuck 1. Therefore, the generation of particles can be suppressedwithout sliding contact between the wafer W and any portion of the spinchuck 1.

In the first to seventh embodiments, the first and second non-rotativemovable members 68, 78 are moved up and down by the motors M1, M2 andthe ball thread mechanisms 61, 62, but the up and down movements of thefirst and second non-rotative movable members 68, 78 may be achieved byemploying any other driving mechanisms such as air cylinders.

In the second embodiment, the clamping members F1 to F3 of the firstclamping member set each have the first and second abutment portions A,B, and the clamping members S1 to S3 of the second clamping member seteach have the third and fourth abutment portions C, D. Alternatively,only the clamping members F1 to F3 may each have two abutment portionsA, B, and the clamping members S1 to S3 may each have one abutmentportion 96 as in the first embodiment. In this case, the wafer clampingstate is once switched from a first state where the wafer W is clampedby the three first abutment portions A of the clamping members F1 to F3to a first intermediate state where the wafer W is clamped by the threefirst abutment portions A of the clamping members F1 to F3 and theclamping members S1 to S3, then to a second state where the wafer W isclamped by the clamping members S1 to S3 and unclamped by the firstabutment portions A, further to a second intermediate state where thewafer W is clamped by the three second abutment portions B of theclamping members F1 to F3 and the clamping members S1 to S3, and to athird state where the wafer W is clamped by the second abutment portionsB and unclamped by the clamping members S1 to S3. Thus, the wafer Wclamping state by the clamping members F1 to F3 is transferred fromclamping by the first abutment portions A to clamping by the secondabutment portions B.

Further, the clamping members F1 to F3 and/or the clamping members S1 toS3 may each include three or more abutment portions which areselectively brought into abutment against the peripheral surface of thewafer W.

In the first to ninth embodiments, the semiconductor wafer is employedas the substrate to be treated, but the present invention is applicableto any other round substrates such as optical disks, and rectangularsubstrates such as glass substrates for liquid crystal display devices.

FIG. 23 is a schematic sectional view for explaining the construction ofa substrate treatment apparatus according to a tenth embodiment of thepresent invention. This substrate treatment apparatus includes a spinchuck 401 for rotating a semiconductor wafer W as an example of agenerally round substrate (hereinafter referred to simply as “wafer”)about a vertical axis extending through the center thereof whilehorizontally holding the wafer W, and a shield plate 402 disposed abovethe spin chuck 401 and having a wafer opposed surface 402 a to belocated adjacent an upper surface of the wafer W held by the spin chuck401. The shield plate 402 has a generally disk shape, and the waferopposed surface 402 a thereof has a round shape having a slightlysmaller diameter than the wafer W. A vertical rotation shaft 403 isconnected to an upper surface of the shield plate 402, and a torque froma shield plate rotative drive mechanism 404 is applied to the rotationshaft 403. A shield plate lift drive mechanism 405 is provided formoving up and down the shield plate 402 with respect to the spin chuck401.

The rotation shaft 403 has a hollow inside in which a treatment liquidsupply pipe 406 is inserted. A distal end portion of the treatmentliquid supply pipe 406 serves as a treatment liquid supply nozzle 407which extends through a through-hole formed in the center of the shieldplate 402 to a position opposed to the center of the upper surface ofthe wafer W held by the spin chuck 401. A treatment liquid such asdeionized water can be supplied to the treatment liquid supply pipe 406via a treatment liquid supply valve 408.

An inert gas supply passage 409 is defined between an interior surfaceof the rotation shaft 403 and the treatment liquid supply pipe 406 inthe rotation shaft 403. An inert gas such as nitrogen gas can besupplied to the inert gas supply passage 409 via an inert gas supplyvalve 410.

The spin chuck 401 includes a disk-shaped spin base 411, a verticalhollow rotary shaft 412 connected to the center of a lower surface ofthe spin base 411, and a chuck rotative drive mechanism 413 for applyinga rotative driving force to the rotary shaft 412. A treatment liquidsupply pipe 415 is inserted through the rotary shaft 412. To thistreatment liquid supply pipe 415, an etching liquid or deionized watercan be supplied from an etching liquid supply source or a deionizedwater supply source via an etching liquid supply valve 416 or adeionized water supply valve 417, respectively. The treatment liquidsupply pipe 415 extends to an upper surface of the spin base 411, anddistal end portion thereof serves as a treatment liquid supply nozzle418 for supplying the etching liquid or deionized water toward thecenter of a lower surface of the wafer W held by the spin chuck 401.

A plurality of support pins 419 for supporting a peripheral edge portionof the lower surface of the wafer W are provided circumferentially ofthe spin base 411 on the upper surface of the spin base 411 (forexample, three support pins are equiangularly provided). A plurality ofclamp pins (six clamp pins) 421 are provided on the spin base 411 forclamping the wafer W on the support pins 419 in abutment against aperipheral surface of the wafer W. In this embodiment, the clamp pins421 are arranged equiangularly circumferentially of the spin base 411.

Movement converting mechanisms 420 are provided in association with therespective clamp pins 421 for causing the clamp pins 421 to clamp andunclamp the wafer W. More specifically, the movement convertingmechanisms 420 each include a rocking lever 424 connected to the clamppin 421 at one end thereof, and a roll 425 as a cam follower rotatablyattached to the other end of the rocking lever 424. The rocking lever424 is coupled to a bracket 422 fixed to the lower surface of the spinbase 411 pivotally about a support shaft 423. The support shaft 423extends horizontally and perpendicularly to a radius of the spin base411. Therefore, the rocking lever 424 is pivotal within a vertical planecontaining the radius of the spin base 411.

A compression coil spring 426 as a biasing mechanism for biasing theclamp pin 421 into a wafer clamping state is provided as extending fromthe lower surface of the spin base 411 to a portion of the rocking lever424 between the support shaft 423 and the roll 425. That is, thecompression coil spring 426 biases the rocking lever 424 downward at aposition radially inward of the spin base 411. Thus, a portion of therocking lever 424 radially outward from the support shaft 423 is movedupward, whereby the clamp pin 421 is biased radially inwardly.

The roll 425 is provided at the end of the rocking lever 424 rotatablyabout an axis of the rocking lever 424. A cam member 430 is providedbelow the roll 425 around the rotary shaft 412. The cam member 430 has acam surface 431 formed on an upper surface thereof opposed to the roll425 as having a shape surrounding the rotary shaft 412.

More specifically, the cam member 430 includes a cylindrical body 432provided rotatably about the rotary shaft 412 with the rotary shaft 412inserted therethrough, and a flange 433 projecting radially outwardlyfrom an upper edge of the body 432. The cam surface 431 is formed on theupper surface of the flange 433.

The cylindrical body 432 is coupled to a bracket 437 via a pair ofbearings 435, 436 fitted around the body 432 as spaced longitudinally ofthe rotary shaft 412. A motor 438 as a cam member rotative drivemechanism for generating a driving force for driving the cam member 430rotatively about the rotary shaft 412 is attached to the bracket 437.The torque of the cam member rotation motor 438 is transmitted to apulley 441 coupled to a lower end portion of the cylindrical body 432via a motor pulley 439 and a timing belt 440.

On the other hand, a cam member lift drive mechanism 443, for example,including a multi-step air cylinder and a ball thread mechanism iscoupled to the bracket 437. The cam member 430 can be moved up and downalong the rotary shaft 412 by operating the cam member lift drivemechanism 443 to move up and down the bracket 437.

FIG. 24(A) is a plan view for explaining the configuration of the camsurface 431, and FIG. 24(B) is a sectional view taken along a sectionline A-A extending circumferentially of the cam surface 431. A pluralityof projections 445 (three projections 445 hatched in FIGS. 24(A) and24(B) in this embodiment) are provided in circumferentially(equidistantly) spaced relation on the cam surface 431 as projectingupward (parallel to the rotary shaft). Troughs 446 defined betweenadjacent projections 445 and 445 each have a planar surface.

In this embodiment, the planar surfaces of the troughs 446 each have anangular span of greater than 60 degrees and, as a result, theprojections 445 each have an angular span of smaller than 60 degrees.The projections 445 each have a chevron shape having upward and downwardgentle slopes extending circumferentially, and apexes of the threeprojections 445 are equiangularly spaced (i.e., at an angular intervalof 120 degrees) on the cam surface 431.

Where the six clamp pins 421-1 to 421-6 are located in a positionalrelationship with respect to the cam surface 431 as shown in FIG. 24(A)when the cam surface 431 is positioned at a proper height, the rolls 425(see FIG. 23) of the movement converting mechanisms 420 for the clamppins 421-1, 421-3, 421-5 are moved upward along the rotary shaft 412. Asa result, the clamp pins 421-1, 421-3, 421-5 are retracted from theperipheral surface of the wafer W thereby to unclamp the wafer W. On theother hand, the rolls 425 of the movement converting mechanisms 420 forthe clamp pins 421-2, 421-4, 421-6 located in association with thetroughs 446 receive no upward thrust force from the cam surface 431.Therefore, the clamp pins 421-2, 421-4, 421-6 are kept in abutmentagainst the peripheral surface of the wafer W by the biasing forces ofthe compression coil springs 426 thereby to clamp the wafer W.

When the cam member 430 is rotated relative to the spin chuck 401 aboutthe rotary shaft 412 in this state, the positional relationship betweenthe clamp pins 421-1 to 421-6 and the projections 445 is changed. As aresult, a wafer clamping state is switched alternately between a firstclamping state where the wafer W is clamped by one set of three clamppins 421-1, 421-3, 421-5 and a second clamping state where the wafer Wis clamped by the other set of three clamp pins 421-2, 421-4, 421-6.Since the planar surfaces of the troughs 446 each have an angular spanof greater than 60 degrees as described above, there is an intermediateclamping state where the wafer W is clamped by all the clamp pins 421-1to 421-6 when the wafer clamping state is switched between the firstclamping state and the second clamping state.

The height of the cam surface 431 can be changed by operating the cammember lift drive mechanism 443. Where the cam surface 431 is located ata sufficiently low level (at an all-closing position), the projections445 of the cam surface 431 are brought into contact with none of therolls 425 of the movement converting mechanisms 420. Thus, all the clamppins 421-1 to 421-6 are kept in the wafer clamping state (closed state).Therefore, the clamp pins 421-1 to 421-6 constantly clamp the wafer W ina first inactive mode, irrespective of the relative rotation of the cammember 430 with respect to the spin chuck 401.

Where the cam surface 431 is located at an intermediate height (at anopening/closing position) such that the rolls 425 are lifted on theprojections 445 and not lifted on the troughs 446, the clamp pins 421-1to 421-6 are opened and closed in association with the relative rotationof the cam member 430 with respect to the spin chuck 401, i.e., inassociation with the rotation of the spin chuck 401, in an active mode.

Further, where the cam surface 431 is located at a sufficiently highlevel (at an all-opening position) such that the rolls 425 are lifted onboth the projections 445 and the troughs 446, all the clamp pins 421-1to 421-6 are retracted from the peripheral surface of the wafer W in aunclamping state (opened state) in a second inactive mode, irrespectiveof the relative rotation of the cam member 430 with respect to the spinchuck 401.

The operations of the chuck rotative drive mechanism 413, the cam memberrotation motor 438, the cam member lift drive mechanism 443, the shieldplate rotative drive mechanism 404 and the shield plate lift drivemechanism 405 are controlled by a control section 450. Further, theopening and closing of the treatment liquid supply valve 408, the inertgas supply valve 410, the etching liquid supply valve 416 and thedeionized water supply valve 417 are controlled by the control section450.

When an untreated wafer W is to be loaded, the control section 450controls the shield plate lift drive mechanism 405 to retract the shieldplate 402 upward above the spin chuck 401. The control section 450controls the cam member lift drive mechanism 443 to lift the cam member430 to the all-opening position, whereby the operation mode is switchedto the second inactive mode in which all the clamp pins 421-1 to 421-6are kept in the wafer unclamping state. In this state, the untreatedwafer W is placed on the support pins 419 on the spin base 411 by atransport robot (not shown). At this time, a device formation surface(active surface) of the wafer W faces upward as opposed to the shieldplate 402.

Next, the control section 450 controls the cam member lift drivemechanism 443 to lower the cam member 430 to the all-closing position,whereby the operation mode is switched to the first inactive mode.Therefore, the wafer W is stably clamped by all the clamp pins 421.Further, the control section 450 controls the shield plate lift drivemechanism 405 to lower the shield plate 402 toward the spin chuck 401,whereby the wafer opposed surface 402 a is located in the vicinity ofthe upper surface of the wafer W.

In this state, the control section 450 controls the shield platerotative drive mechanism 404 and the chuck rotative drive mechanism 413to synchronously rotate the spin chuck 401 and the shield plate 402, forexample, in the same direction at substantially the same rotation speed.At the same time, the control section 450 opens the inert gas supplyvalve 410 to supply the inert gas to the upper surface of the wafer W.The control section 450 opens the etching liquid supply valve 416 tosupply the etching liquid from the treatment liquid supply nozzle 418toward the center of the lower surface of the wafer W.

The control section 450 controls the cam member rotation motor 438 torotate the cam member 430 for relative rotation of the cam member 430with respect to the spin chuck 401 at a predetermined speed. Forexample, it is preferred that the cam member 430 and the spin chuck 401are rotated in the same direction and a difference in rotation speedbetween the spin chuck 401 and the cam member 430 is 10 rpm to 300 rpm(more preferably about 60 rpm).

After the spin chuck 401 is accelerated to a predetermined rotationspeed to be rotated at the constant rotation speed, the control section450 controls the cam member lift drive mechanism 443 to lift the cammember 430 to the opening/closing position at the intermediate height.At the opening/closing position, the rolls 425 are lifted on theprojections 445 of the cam surface 431, but not lifted on the troughs446. Thus, the three clamp pins 421-1, 421-3, 421-5 arranged at anangular interval of 120 degrees are synchronously opened and closed,while the other three clamp pins 421-2, 421-4, 421-6 arranged at anangular interval of 120 degrees are synchronously opened and closed. Theset of the three clamp pins 421-1, 421-3, 421-5 and the set of the threeclamp pins 421-2, 421-4, 421-6 are opened and closed in alternatelystaggered timing relation. Thus, the wafer clamping positions can bechanged, while the wafer W is constantly clamped by either or both ofthe sets of the clamp pins 421.

The etching liquid supplied to the center of the lower surface of thewafer W from the treatment liquid supply nozzle 418 flows over the lowersurface of the wafer W radially outwardly of the wafer W by acentrifugal force, and then flows over the peripheral surface of thewafer W to reach the peripheral edge portion of the upper surface of thewafer W. Thus, a so-called bevel etching process or bevel cleaningprocess can be performed by etching away an unnecessary substance fromthe peripheral surface of the wafer W and the peripheral edge portion ofthe upper surface of the wafer W. During the bevel etching process orthe bevel cleaning process, the clamp pins 421 are opened and closed tochange the wafer clamping positions. Therefore, the peripheral surfaceof the wafer W and the peripheral edge portion of the upper surface ofthe wafer W can entirely and properly be subjected to the etchingprocess.

The amount of the etching liquid flowing onto the upper surface of thewafer W is controlled by controlling the rotation speed of the spinchuck 401, the distance between the shield plate 402 and the uppersurface of the wafer W and the flow rate of the inert gas supplied tothe upper surface of the wafer W.

Upon completion of the bevel etching process, the control section 450closes the etching liquid supply valve 416, and opens the deionizedwater supply valve 417. Thus, deionized water is supplied from thetreatment liquid supply nozzle 418 toward the center of the lowersurface of the wafer W, whereby a deionized water rinse process isperformed for rinsing off the etching liquid from the surface of thewafer W. At this time, the treatment liquid supply valve 408 is openedunder the control of the control section 450 to supply deionized waterto the upper surface of the wafer W as required.

During the deionized water rinse process, the set of the clamp pins421-1, 421-3, 421-5 and the set of the clamp pins 421-2, 421-4, 421-6are opened and closed in alternately staggered timing relation, so thatthe entire surface of the wafer W can properly be rinsed.

Upon completion of the rinse process, the control section 450 closes thedeionized water supply valve 417 and, if the treatment liquid supplyvalve 408 is opened, closes the valve 408. Thereafter, the controlsection 450 controls the cam member lift drive mechanism 443 to move thecam member 430 down to the all-closing position, and then stops themotor 438. Thus, all the clamp pins 421 are brought into the waferclamping state. In this state, the control section 450 controls thechuck rotative drive mechanism 413 and the shield plate rotative drivemechanism 404 to accelerate the rotation of the spin chuck 401 and theshield plate 402 so as to rotate the wafer W at a high speed. Thus, adrying process is performed by spinning off water from the surface ofthe wafer W by a centrifugal force. During the drying process, the waferW is stably clamped by all the clamp pins 421-1 to 421-6.

After the spin chuck 401 is rotated at a high speed for a predeterminedperiod to complete the drying process, the control section 450 controlsthe shield plate rotative drive mechanism 404 and the chuck rotativedrive mechanism 413 to stop the rotation of the spin chuck 401 and theshield plate 402. Further, the control section 450 controls the shieldplate lift drive mechanism 405 to lift the shield plate 402 upward tothe retracted position above the spin chuck 401. Further, the controlsection 450 controls the cam member lift drive mechanism 443 to lift thecam member 430 to the all-opening position. Thus, all the clamp pins 421are brought into the wafer unclamping state. In this state, the treatedwafer W is unloaded from the support pins 419 by the transport robot.

In this embodiment, the clamp pins 421 can thus be opened and closed inassociation with the rotation of the spin chuck 401 simply by rockingthe rocking levers 424 by means of the cam mechanism. The set of thethree clamp pins 421-1, 421-3, 421-5 and the set of the three clamp pins421-2, 421-4, 421-6 clamp the wafer W in alternately staggered timingrelation, so that the entire peripheral surface and peripheral edgeportion of the wafer W can properly be treated without the relativerotation of the wafer W with respect to the spin chuck 401. Therefore,the abrasion of the clamp pins 421 can be suppressed.

In addition, the wafer W is clamped by all the clamp pins 421-1 to 421-6in the intermediate clamping state when the wafer clamping state isswitched between the first clamping state with the wafer W clamped bythe three clamp pins 421-1, 421-3, 421-5 and the second clamping statewith the wafer W clamped by the three clamp pins 421-2, 421-4, 421-6.Therefore, the wafer W is constantly stably held by all or some of theclamp pins 421. This eliminates an unstable wafer holding period.Accordingly, there is no possibility that the wafer W is spun out of thespin chuck 401. Further, the shield plate 402 can assuredly be spaced aminute distance from the wafer W, whereby the amount of the etchingliquid flowing onto the upper surface of the wafer W can strictly becontrolled. This makes it possible to precisely treat the peripheraledge portion of the wafer w.

In this embodiment, the cam member 430 is rotatable about the rotaryshaft 412, and the rotation speed of the cam member 430 can becontrolled independently of the rotation speed of the spin chuck 401.Therefore, a clamp pin opening and closing interval can properly be set.As required, the clamp pin opening and closing interval may be variedduring the treatment of the wafer W.

By moving up and down the cam member 430, the operation mode can beswitched among the first inactive mode where the clamp pins 421 are keptin the wafer clamping state, the second inactive mode where the clamppins 421 are kept in the wafer unclamping state, and the active modewhere the clamp pins 421 are alternately switched between the waferclamping state and the wafer unclamping state. Thus, the operation modeof the clamp pins 421 can be switched with the simple construction.

Although the three projections 445 are provided in circumferentiallyspaced relation on the cam surface 431 in the embodiment describedabove, four projections 445 may be provided on the cam surface 431 asshown in FIG. 25(A). Alternatively, six projections 445 may be providedin circumferentially spaced relation on the cam surface 431 as shown inFIG. 25(B), or two projections 445 may be provided in opposed relationabout the rotation center as shown in FIG. 25(C). With any of thesearrangements, the plurality of clamp pins can be switched between thewafer clamping state and the wafer unclamping state.

With the arrangement shown in FIG. 25(C), for example, the six clamppins 421-1 to 421-6 are sequentially brought into the wafer unclampingstate with each opposed pair of clamp pins about the rotary shaft beingopened and with the other four clamp pins being closed to clamp thewafer W.

With the arrangement shown in FIG. 25(B), the six clamp pins 421-1 to421-6 are simultaneously opened or closed. Where it is desired torelatively rotate the wafer W on the spin chuck 401, this arrangement ispreferably employed. That is, if the abrasion of the clamp pins 421 isnot a serious problem, the rotational position of the wafer W relativeto the spin chuck 401 may be changed by accelerating or decelerating therotation of the spin chuck 401 with all the clamp pins 421 being openedwhen the treatment is performed by supplying the treatment liquid suchas the etching liquid to the wafer W.

In general, however, the configuration and arrangement of theprojections 445 on the cam surface 431 are preferably determined so asto prevent each adjacent pair of clamp pins 421 from beingsimultaneously brought into the unclamping state when the cam member 430is located at the opening/closing position. Thus, the relative rotationof the wafer W with respect to the spin chuck 401 can be suppressed.

In the embodiment described above, the wafer W is clamped by the sixclamp pins 421 disposed circumferentially of the wafer in equiangularlyspaced relation. However, any number of clamp pins may be employed aslong as the wafer W can properly be held.

Further, the clamping members for clamping the wafer W are notnecessarily required to have a pin shape, but arcuate clamping members421A, 421B, 421C, 421D, or 421 a, 421 b, 421 c may be employed which areeach brought into line contact with the peripheral surface of the waferW over a predetermined angular span as shown in FIG. 26(A) or 26(B).

With the arrangement shown in FIG. 26(A), for example, the four arcuateclamping members 421A, 421B, 421C, 421D are disposed in equiangularlyspaced relation, and are each brought into line contact with theperipheral surface of the wafer W over an angular span of about 90degrees, whereby the wafer W can be clamped by either of the two pairsof clamping members 421A, 421C; 421B, 421D disposed in opposed relationabout the rotation center. Even if the two pairs of clamping members421A, 421C; 421B, 421D are alternately opened and closed during thetreatment with the etching liquid or the like, the wafer W can stably beheld by either of the two pairs of clamping members 421A, 421C; 421B,421D.

With the arrangement shown in FIG. 26(B), the three arcuate clampingmembers 421 a, 421 b, 421 c are disposed in equiangularly spacedrelation, and are each brought into line contact with the peripheralsurface of the wafer W over an angular span of about 120 degrees. Theseclamping members 421 a, 421 b, 421 c are circularly opened and closedone by one, whereby the wafer W can stably be held over an angular spanof about 240 degrees (i.e., over an angular span of greater than 180degrees) for properly treating the peripheral edge portion of the waferW.

In the embodiment described above, the substrate treatment apparatus isadapted to perform the bevel etching process or the bevel cleaningprocess while holding the peripheral surface of the wafer W. However,the inventive substrate treatment apparatus may be embodied as asubstrate treatment apparatus which is adapted to perform a treatmentprocess by supplying the treatment liquid such as the etching liquidover the entire surface of the substrate in addition to the beveletching process or the bevel cleaning process.

In the embodiment described above, the cam member 430 is disposedrotatably about the rotary shaft 412, but the cam member 430 may bedisposed in a non-rotatable manner about the rotary shaft 412. In thiscase, the clamp pin opening and closing interval depends on the rotationspeed of the spin chuck 401 alone.

In the embodiment described above, the wafer W is employed as thesubstrate to be treated by way of an example. However, the presentinvention is applicable to substrate treatment apparatuses for treatingany other types of round substrates such as for optical disks andmagnetic disks and substrate treatment apparatuses for treatingrectangular substrates such as glass substrates for liquid crystaldisplay devices.

While the present invention has been described in detail by way of theembodiments thereof, it should be understood that the foregoingdisclosure is merely illustrative of the technical principles of thepresent invention but not limitative of the same. The spirit and scopeof the present invention are to be limited only by the appended claims.

This application corresponds to Japanese Patent Applications No.2002-218723 and No. 2002-218724 filed with the Japanese Patent Office onJul. 26, 2002, No. 2002-281628 filed with the Japanese Patent Office onSep. 26, 2002, and No. 2003-83695 and No. 2003-83696 filed with theJapanese Patent Office on Mar. 25, 2003, the disclosure of which isincorporated herein by reference.

1. A substrate treatment apparatus comprising: a rotary member having arotary shaft and a plurality of clamping members which are capable ofclamping and unclamping a substrate, the rotary member being rotatableabout the rotary shaft; a rotative drive mechanism for applying a torqueto the rotary shaft to rotatively drive the rotary member; anon-rotative movable member which is movable parallel to the rotaryshaft; a driving mechanism for moving the non-rotative movable memberparallel to the rotary shaft; a rotative movable member which is movableparallel to the rotary shaft in association with movement of thenon-rotative movable member by a driving force received from thenon-rotative movable member and is rotatable together with the rotarymember; a movement converting mechanism for converting movement of therotative movable member into movements of the clamping members of therotary member; and a controller for operating the driving mechanism sothat the substrate is completely or slightly released from the clampingmembers and then clamped again by the clamping members while the rotarymember is rotated by the rotative drive mechanism; wherein thenon-rotative movable member is movable parallel to the rotational axisof the rotary shaft, and the rotative movable member is movable parallelto the rotational axis of the rotary shaft, so that both thenon-rotatable movable member and the rotative movable member are movableparallel to the rotational axis of the rotary shaft.
 2. A substratetreatment apparatus as set forth in claim 1, wherein at least one of thenon-rotative movable member and the rotative movable member isconfigured annularly about the rotary shaft.
 3. A substrate treatmentapparatus as set forth in claim 1, wherein the controller controls therotative drive mechanism to accelerate or decelerate the rotation of therotary member when the substrate is completely or slightly released fromthe clamping members.
 4. A substrate treatment apparatus as set forth inclaim 1, wherein the clamping members each have a first abutment portionand a second abutment portion which are selectively brought intoabutment against the substrate, wherein the controller operates thedriving mechanism so that the first abutment portion and the secondabutment portion are switchably brought into abutment against thesubstrate during the rotation of the rotary member.
 5. A substratetreatment apparatus as set forth in claim 1, further comprising adriving force transmission mechanism for transmitting a driving forcefrom the non-rotative movable member to the rotative movable memberwhile permitting relative rotation of the rotative movable member withrespect to the non-rotative movable member about the rotary shaft.
 6. Asubstrate treatment apparatus as set forth in claim 5, wherein thedriving force transmission mechanism comprises an annular bearing whichcouples the non-rotative movable member and the rotative movable memberso as to permit the relative rotation of the rotative movable memberwith respect to the non-rotative movable member about the rotary shaft.7. A substrate treatment apparatus as set forth in claim 5, wherein thedriving force transmission mechanism comprises a plurality of rollingmembers provided on at least one of the non-rotative movable member andthe rotative movable member so as to be rolled on a surface of the othermovable member.
 8. A substrate treatment apparatus as set forth in claim5, wherein the driving force transmission mechanism comprises astationary magnet and a rotary magnet respectively provided on thenon-rotative movable member and the rotative movable member with opposedpoles thereof having the same polarity.
 9. A substrate treatmentapparatus as set forth in claim 5, wherein the driving forcetransmission mechanism comprises a gas supply mechanism for supplying agas between the non-rotative movable member and the rotative movablemember so as to keep the non-rotative movable member and the rotativemovable member in spaced relation.
 10. A substrate treatment apparatusas set forth in claim 1, further comprising a treatment fluid supplymechanism for supplying a treatment fluid to a surface of the substrateheld and rotated by the substrate holding mechanism.
 11. A substratetreatment apparatus as set forth in claim 10, wherein the treatmentfluid supply mechanism comprises an etching liquid supply mechanism forsupplying an etching liquid for removing an unnecessary substance from aperipheral edge portion of the substrate held and rotated by thesubstrate holding mechanism.